Preheat oven to 350°F (175°C).

In a bowl, mix ground beef with onion powder, and season with salt and pepper; form into 8 small patties.

Cook patties in a skillet over medium-high heat for about 3 minutes per side; add cheese during the last minute.

Slice rolls in half horizontally; place the bottom half in a baking dish. Layer cooked patties on top and add ketchup, mustard, pickles, lettuce, and tomato.

Cover with the top half of the rolls and bake for an additional 5 minutes until heated through.