Mill the spelt berries on the finest setting of your grain mill. In a small bowl, whisk together the freshly milled flour, baking powder, baking soda, cinnamon, and salt.
In a large bowl, beat the butter and sugar until pale and fluffy. Add the eggs one at a time, beating briefly after each addition.
Gradually fold in the dry ingredients until just combined, then gently fold in the grated carrots. The batter will be quite thick.
Rest the batter while the oven preheats to 175°C (350°F).
Make the Frosting
While the oven preheats and the batter rests, make the frosting.
Europe: Beat the butter until pale and fluffy. Add the cream cheese and beat gently just until combined. Stir in the maple syrup on the lowest mixer setting or fold it in by hand. Do not overbeat. Cover and refrigerate until ready to use.
North America: Beat the cream cheese until smooth and softened. Add the butter and mix to combine well. Stir in the maple syrup on the lowest mixer setting or fold it in by hand. Do not overbeat. Cover and refrigerate until ready to use.
Bake the Cake or Cupcakes
For a layer cake: Transfer the batter to a prepared 23-cm/9-inch deep cake pan and spread evenly. Bake for about 50 minutes, or until a toothpick inserted in the center comes out clean. The internal temperature should be around 95°C (203°F).
Cool in the pan for 15 minutes, then loosen the edges with a knife and transfer the cake to a cooling rack. Cool completely before frosting.
For 24 cupcakes: Divide the batter evenly among 24 lined muffin cups. Bake until a toothpick inserted into the center comes out clean. Cool in the pan for 10 minutes, then transfer to a cooling rack and cool completely before frosting.
Finish
For the layer cake: Using a long, sharp knife, slice the cooled cake into three even layers. Stack the layers with frosting between them, then use the remaining frosting to cover the top and sides.
For the cupcakes: Fill the maple cream cheese frosting into a piping bag and frost the cooled cupcakes.
Decorate as desired and enjoy!
Notes
You can also use three 23-cm/9-inch round shallow cake pans to bake individual cake layers. Adjust baking time to 20-25 minutes if you do.
You can add 1/2 cup of your favorite add-ins to the batter: chopped pistachios, almonds, hazelnuts, walnuts or pecans, shredded coconut, raisins soaked in black tea (well drained), drained chopped pineapple
Decorate with your choice of toppings: sprinkles, toasted coconut flakes, chopped pistachios, marzipan carrots, or whole candied walnut halves.