I used a bunch of leftover stuff,
Cup of white cheddar
Mustard
nutmeg,
4 tbsp of butter
Packet of 8 brioche buns that were a bit stale, diced
1.5 Onions,
Parsley,
Half packet of prosciutto,
I use this bechamel recipe
Bechamel. And put half a cup of cheddar, 2 eggs, and a little more nutmeg in a bowl and whisked, then added the dice the bread up and covered with enough bechamel to coat it evenly when tossed.
Caramelized the onions with lots of butter and sliced the prosciutto.
Then I put the soggy bread/egg mixture in a greased 13x9, added the onions and prosciutto in an even layer, sprinkled another half cup of cheese over it and baked for 25 minutes covered, and 15 uncovered on 400, middle rack.