Melt the butter and let it cool down. Mix flour and eggs. Gradually stir in milk and mineral water. Finally, stir in liquid butter. Let dough rest for about 30 minutes.
Peel oranges so that the white skin is completely removed. Then cut into slices. Brush a pan with a little oil. Pour some batter into the pan and spread it thinly on the bottom of the pan by swinging it back and forth.
Bake from both sides until golden brown. Sprinkle with about 2 tablespoons of liqueur and light with a burning match. Let it burn while swinging until the flame goes out by itself. Do the same with the rest of the dough.
Briefly toss orange slices in the frying fat. Sprinkle crépes with sugar and cinnamon, add orange slices.