Preheat an oven to 350 degrees F (175 degrees C). Lightly grease a 12 cup muffin pan.

Mix ground beef, soup, onion, bread crumbs, eggs, salt, and pepper in a bowl. Scoop mixture evenly into prepared muffin cups.

Bake 1 hour in the preheated oven to a minimum temperature of 160 degrees F (70 degrees C). If desired, remove from oven after 50 minutes, drizzle ketchup on the top of each muffin, and return to oven for an additional 10 minutes.