Finely blend the Brazil nuts in a food processor, beat the eggs with the maple syrup until frothy.
Finely grate the carrots and apples, mix with buttermilk, cornstarch, eggs and Brazil nuts. Pour everything into a baking pan and bake at 170 °C top and bottom heat for about 40 minutes.
Remove the cake from the oven, let it cool a bit and cut it into small pieces.