Sourdough Discard Apple Cake with Freshly Milled Flour

Name: Freshly Milled Sourdough Discard Apple Cake
Prep time: 25 min
Cook time: 45 min
Total time: 70 min
Ingredients: 100 g oat groats ((~½ cup) or oat flour); 100 g whole soft wheat berries ((~½ cup) see Ingredients for swaps); 100 g blanched ground almonds ((~1 cup) blanched almond flour); 1 1/2 tsp baking powder; 2 tsp pumpkin spice; ¼ tsp fine sea or table salt; 110 g refined coconut oil, melted ((½ cup) or other neutral oil); 165 g light brown sugar, packed ((¾ cup)); ½ tsp vanilla extract (optional); 3 large eggs, separated; 120 g sourdough discard ((½ cup) or active starter); 1 medium apple, grated ((~½ cup)); 3-4 medium apples (thinly sliced); 30 g melted butter ((2 tbsp) or more coconut oil); 1 tsp cinnamon

A soft and fluffy apple cake made with freshly milled soft wheat & oat flours, ground almonds, sourdough discard, pumpkin spice, and plenty of fresh apple.

JUMP TO RECIPE

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Closeup of one piece of fresh milled sourdough apple cake being lifted off the plate, showing the soft crumb and juicy baked apples.

This is the apple cake recipe I’ve been making for years, even before I had a grain mill or understood the concept of “discard recipes”.

I have always loved it for its blend of oats, almonds, and wheat that forms a deliciously rich and complex base. It’s a real fall cake that not only carries all the cozy flavors of pumpkin pie spice, but actually uses up a good amount of apples too.

We’ve been enjoying this cake all through September, fine tuning the recipe to using fresh milled flours and sourdough discard. It made the cake even more delicious, and it actually improved the texture.
Proof that fresh milled flour is not a compromise.

I particularly love a slice of this cake for an early afternoon fuel up. With fresh milled whole grains and just enough brown sugar to make it worthwhile, it’s the kind of treat that gives you actual energy before you have to get back out and continue apple picking.

More freshly milled Cake Recipes:

Why You’ll Love This Recipe

Just sweet enough » Just enough brown sugar makes this cake sweet enough to be a treat, but keeps it light enough to gallantly pass for breakfast.
Full of apples » This is a proper fall cake. One grated apple for the batter, and three to four apples to fan across the top. Perfect for those with an apple tree in their yard, or those of us that briefly lose touch with reality whenever we go apple picking.
Grain blend » A combination of almond flour, and fresh milled oat and soft wheat flours gives this cake a deeper, richer flavor that pairs so well with cozy fall spices and juicy apples.
Tastes like fall » Oat and almond flours add a lovely complex flavor to a pumpkin pie spiced batter. Brushing the apples with melted butter and cinnamon makes them bake up extra juicy and cozy.

Tools You May Need

Grain mill: I love fresh milled flour for the most intense flavor, but the recipe still works great with store bought whole grain flour.

Hand mixer or stand mixer: For whipping egg whites into stiff peaks that make the cake soft, tall, and fluffy.

Grater: For grating one apple into the batter.

9×13-inch (23×33-cm) cake pan: I use a metal pan. You may need to adjust baking times for glass or ceramic pans.

Ingredients & Substitutions

Overhead view of all the ingredients for sourdough discard apple cake laid out on a white worktop.

Freshly milled flours: I use a mix of soft wheat berries and whole oat groats. You can use any variety of soft wheat, either white, red, or yellow.

If you’re unsure about grinding whole oat groats, you can just swap store-bought oat flour, or grind rolled oats very finely in a food processor. To replace freshly milled soft wheat, regular whole wheat flour can be used in most European countries. In North America, whole wheat pastry flour is the closest match.

Blanched ground almonds: The terminology can be a little vague, but I’m using finely ground blanched almonds, sometimes called almond flour. It doesn’t need to be super fine and powdery, but it should be fine and uniform.

Pumpkin pie spice: Use your favorite homemade pumpkin pie spice, a familiar blend from the store, or just substitute with cinnamon in a pinch.

Oil: I prefer refined coconut oil which is neutral in taste. If you don’t mind the coconut flavor, feel free to use regular coconut oil, or sub with any other neutral tasting oil.

Eggs: Whipping the egg whites to stiff peaks gives the batter a lift and makes the crumb extra soft and fluffy. I know it’s an extra step, but please don’t skip it.

Sourdough discard: You can use sourdough discard straight from the fridge or at room temperature. If it smells very sour, you can do a Discard Reset first.
You can also use active bubbly starter for a milder taste. (Be sure to measure it by weight, or to stir it down if you’re using cups.)

Apples: Use any variety you love (or need to use up). I grate and slice my apples whole, so I always go for unwaxed, preferably organic apples. If you can’t, peel your apples first. Freshly picked apples are the best, obviously.

Butter: I love brushing the apples with melted butter and cinnamon before baking. The smell reminds me of fresh cinnamon rolls, but if you need a dairy-free cake, you can just use a little more coconut oil instead.

A Word About Freshly Milled Oat Flour

Please note:
Not all grain mills are designed to grind oat groats on the finest setting. Check your mill’s instructions before starting.
Rolled or steel cut oats are not suitable for milling. Always use whole oat groats that only have the husk removed.

Oat groats tend to have a higher moisture and oil content than wheat or other grains. If you mill them on the finest setting, they can sometimes stick to the stones of some mills.

I use the KoMo Duett 100 which is compatible with grinding oats. However, I find that the stones of my mill still get sticky and jam when finely grinding oat groats by themselves.

However, whenever I mix wheat berries and oat groats very well before milling, my mill doesn’t struggle at all. Nothing sticks to the stones, nothing jams, and the stones look completely clean afterwards.

How to Make Sourdough Discard Apple Cake (Step-by-Step)

Step 01

Combine dry ingredients

Freshly milled flour is falling from the spout of a wooden home grain mill into a ceramic bowl underneath.

Weigh out oat groats and soft wheat berries and mix them really well until combined evenly. Mill them on the finest setting of your grain mill.
Add the blanched ground almonds, baking powder, pumpkin pie spice, and salt and stir to combine.

Step 02

Combine wet ingredients

Wet ingredients for sourdough apple cake have been stirred together in a large ceramic bowl, with the rest of the ingredients layed out beside it.

In a large mixing bowl, whisk together brown sugar, melted coconut oil, vanilla extract, and egg yolks until well combined. Add sourdough discard and whisk again until completely smooth. Stir in the grated apple, juices and all.

Step 03

Combine wet & dry ingredients

Thick batter for fresh milled sourdough apple cake resting in a large ceramic bowl, mixed with a rubber spatula.

Add the dry ingredients to the wet ingredients and fold in until well combined.
Rest the batter while you prepare the rest.

Step 04

Slice apples & whip egg whites

A pale blue bowl filled with whipped egg whites, holding stiff peaks.

Preheat the oven to 180°C (355°F).
Grease the baking pan with butter and line with parchment paper (optional but recommended.)
Wash, core, and thinly slice the apples.
Whip the egg whites to stiff peaks with a hand or stand mixer.

Step 05

Fold in egg whites

Smooth and airy sourdough cake batter has been folded gently with a white rubber spatula on a ceramic bowl, next to a stack of small empty bowls.

Carefully fold a third of the whipped egg whites into the thick, rested batter.
Add another third and fold in until almost combined, then add the rest of the whipped egg whites.
Fold in gently until no visible streaks remain.

Step 06

Arrange in Pan

Fresh milled sourdough cake batter has been spread into an even layer in a lined baking pan, topped with sliced apples.

Transfer the batter to the lined baking pan and smooth the top.
Stack the sliced apples in long, alternating rows.

Step 07

Brush with butter

Closeup of finely sliced apples stacked on the cake batter, being brushed with melted cinnamon butter.

Stir the cinnamon into the melted butter. Brush the apples until everything is evenly coated and all the cinnamon butter is used up.

Step 08

Bake & cool

Golden baked fresh milled sourdough apple cake is resting in the pan set on a black wire rack.

Bake on the lower middle rack for 45 minutes or until a toothpick inserted in the center of the cake comes out clean.
Cool on a wire rack for at least 15 minutes before serving.

Tips & Troubleshooting

If you’re unsure of whether your mill can handle grinding oats, you can either sub with store bought oat flour, or pulse rolled oats in a food processor until broken down evenly.
The batter will be pretty thick after the rest. Fold in the first third of the egg whites well, to loosen the batter. Fold the rest in very carefully, so you don’t deflate the egg whites more than necessary.
Slice apples as finely as you can so they bake into soft, jammy bites.
You can peel the apples before slicing, if they have a very firm or waxy skin.
Make sure that bowl and beaters are completely clean and dry when you whip the egg whites. Even tiny traces of fat or water can stop the whites from fluffing up.
My daughter lovingly refers to the stacked apples as a mermaid’s tail, but you could also stack them in even rows if that makes cutting and serving easier for you.
Use a sharp knife to cut cleanly through the apples on the cooled cake.

How to Serve Fresh Milled Sourdough Discard Apple Cake

Breakfast:
Totally acceptable. Enjoy a slice with a dollop of Greek yogurt and a cup of coffee.
Lunch:
I actually love a slice of this apple cake for an early afternoon fuel up. Sweet enough to be a treat, wholesome enough to give you energy.
Afternoon tea:
Enjoy a warm slice with some lightly sweetened whipped cream and a cup of hot chai tea.

Overhead view of golden sourdough apple cake cut into squares, and two pieces topped with a dollop of bright white whipped cream.

How to Store & Freeze

At room temperature:
Store at room temperature, loosely covered, for no longer than one day. The apples keep the cake moist, but they also make it spoil faster.

In the fridge:
Leftover cake keeps in the fridge, covered well, for up to 3-4 days. Bring to room temperature or warm in short bursts in the microwave before serving.

In the freezer:
Wrap separate pieces in multiple layers of plastic wrap and freeze for up to 2 months. Thaw at room temperature or overnight in the fridge.

Recipe FAQs

Yes, you can cover and rest the batter for up to 12 hours in the fridge after mixing wet and dry ingredients. When ready, bring it back to room temperature, whip the egg whites, and continue with the rest of the recipe as written.

I generally prefer old varieties with a thin, matte skin, and plenty of flavor. Sweeter apples are a better match here than tart, since the batter isn’t overly sweet. If you have any mealy apples around, use them! They’re perfect for baking and turn extra fork tender in the oven.

Use a store-bought oat flour if you have it, or simply run rolled oats through a food processor or high speed blender.

If you don’t have any discard or fresh sourdough starter at hand, you can sub with plain whole milk yogurt. The cake won’t be quite as fluffy, but still soft and delicious.

If you make this Fresh Milled Sourdough Discard Apple Cake…

I’d love to hear how it turned out!
Let me know in the comments below.
Leave a star rating.
Or save it for later on Pinterest!

P.S. If you’re ready to dive deeper into fall baking, you might love these recipes too:

happy baking!

Inspired by GreenKitchenStories many many years ago.

Prep Time:25

Cook Time:45

Total Time:1 10

Servings:12 slices

Calories:350kcal

Equipment

grain mill
stand mixer or hand mixer - for whipping egg whites
box grater
9×13-inch baking pan (23×33 cm)

Ingredients

Dry Ingredients

100 g oat groats - (~½ cup) or oat flour
100 g whole soft wheat berries - (~½ cup) see Ingredients for swaps
100 g blanched ground almonds - (~1 cup) blanched almond flour
1 1/2 tsp baking powder
2 tsp pumpkin spice
¼ tsp fine sea or table salt

Wet Ingredients

110 g refined coconut oil, melted - (½ cup) or other neutral oil
165 g light brown sugar, packed - (¾ cup)
½ tsp vanilla extract - optional
3 large eggs, separated
120 g sourdough discard - (½ cup) or active starter
1 medium apple, grated - (~½ cup)

Topping

3-4 medium apples - thinly sliced
30 g melted butter - (2 tbsp) or more coconut oil
1 tsp cinnamon

Instructions