Mix the buck wheat flour, the flour, salt, and black pepper in a bowl.
Add the milk and mix well.
Add the olive oil and the egg and stir together.
Let the crêpe batter rest cold for 30 minutes.
Cut the goat cheese in tranches.
Take out the crêpe batter and stir. If the batter is too thick, you can add some more milk.
Heat up a frying pan and melt some of the butter.
Cover the bottom of the frying pan with a thin layer of the crêpe batter.
Flip the crêpe on the other side. Place some cheese, walnuts, and goat cheese in the middle of the crepe.
Fold the edges towards the middle so you have a square. Serve warm immediately.