First prepare ingredients
Melt butter in a pot
Cut you onions in either wedges or rings, then throw them into the pot
Then stir onions until it has a beautiful golden color
Then add flour
Add voille du veau
then put it together! start with a layer or bread underneath, then add your soup, then another layer of bread and grated cheese on top.
Then pop it in the oven at a low temperature until the cheese is golden