Start preheating the oven to 350F/175C. Grease a medium-small size baking dish and set aside.
Peel and core the apples, then slice them into bite-size pieces and set aside.
Cream the softened butter with brown sugar in a large mixing bowl using an electric mixer until light and creamy (about 3-5 minutes).
Add the room-temperature eggs one at a time and incorporate them with a mixer until the dough is smooth.If your eggs are even slightly cold, your mixture will curdle as you see in the picture.While curdling takes away from the fluffiness of the cake, you can still you the batter for baking.
Mix all of the dry ingredients in a separate medium-size bowl and whisk to combine.
Add the wet and dry ingredients together and mix with a whisk until incorporated. Don't overmix!
Finally, fold in the apples with a rubber spatula.
Transfer the buckwheat cake batter to the greased baking dish and smooth out the top with a spatula.Place the dish into the preheated oven at 350F/170C. Bake the cake for 40-45 minutes or until a toothpick comes out clean. Enjoy!
Notes
Storage Store buckwheat apple cake in an air-tight container in the fridge for 3-4 days or freeze it for up to 3 months.To freeze, simply place the cake into a freezer-friendly container and put it in the freezer. To defrost, pop the cake into a microwave for a minute or two!For more details, refer to the Substitutes and FAQ sections.