Preheat the oven to 180 °C top and bottom heat.
Separate the 4 eggs and beat the egg whites with a pinch of salt, vanilla sugar and 40 g sugar until stiff. Wash, peel and grate the apples.
In a second bowl, beat the butter, 60 g sugar, egg yolks and lemon juice until fluffy. Then mix the wholemeal buckwheat flour, ground hazelnuts, baking powder and cinnamon together well, add to the muffin batter and stir in briefly. Then stir in the grated apples and carefully fold in the beaten egg whites.
Pour the buckwheat muffin batter into 12 moulds or a greased muffin tray and bake for approx. 20 minutes.
TIP: To check whether the muffins are done, insert a wooden stick into a muffin and take it out again. If there is any dough left on the stick, the muffins should be baked for a while longer
