Here's a really quick lunch I made today, adapted from one of my cookbooks that features only sandwiches.
Several slices of thick-cut roast beef from the deli
Small onion, sliced
Put buns on a baking sheet and spread cream cheese generously on both sides. Sprinkle with garlic powder to taste. Broil in the oven until browned.
Melt butter in a skillet. Brown the onion slices, and then add the roast beef and heat through.
Put the onions and beef on the buns and enjoy!