1Preheat the oven to 350°F. Grease and line the base and side of a 8-inch round springform pan with parchment paper.
2Put the buckwheat and quinoa flakes in the blender and secure the lid. MILL for 30 seconds until finely ground.
3Add the sugar, baking powder and cinnamon to the blender. STIR for 10 seconds until combined.
4Add the eggs, milk, oil, apple sauce and vanilla to the blender and secure the lid. STIR for 30 seconds. Use a spatula to combine any remaining dry ingredients to avoid over mixing.
5Spoon the batter into the prepared pan. Arrange the apple slices over the top.
6Bake for 45-55 minutes until a skewer inserted in the center comes out clean.
7Let the cake cool in the pan for 5 minutes. Remove from the pan and transfer to a wire rack. Brush the top of the hot cake with jam. Set aside to cool.