My neighbor Kate brought this to the block party and it was so good.  I’ve taken it for staff appreciation snacks and other events and it’s always demolished.

2 Tbsp butter
1 onion, diced up
1 Tbsp Worcestershire sauce
2 Tbsp Dijon mustard
Bread or rolls (I often buy whole wheat dinner rolls which come joined together.)
Brie or Swiss cheese
Turkey ham or real ham

Heat butter in a skillet. Add onions and saute until onion is soft and brown. Add mustard and Worcestershire sauce. Stir

Carefully cut the entire package of rolls in half horizontally. Try not to pull the individual rolls apart. It’s okay if some break apart, but easier to reassemble if they’re together. Slide the bottoms into a 9 x 12 baking dish.

Spread half the mustard mixture on the bottom section of rolls, then layer sliced cheese and turkey ham slices over the top. Spread the rest of the mustard on the top half of the rolls, and carefully place them back on the turkey ham. Cover tightly with aluminum foil. Bake sandwiches at 350 for 10-15 minutes until the bread is nice and toasty, and the cheese is melted. Serve warm with a sharp knife to cut through the sandwiches.