Preheat the oven to 400 degrees F.

Combine ground beef, bread crumbs, egg, onion soup mix, water, and pepper in a large bowl.

Press the meat mixture onto a baking sheet.

Cover the top of the meat with a sheet of parchment paper and use a rolling pin to roll the ground beef completely flat, about 1/2” thick.

Prick holes with a fork through the mixture for ventilation while cooking.

Bake in the preheated oven until browned and cooked through, about 10 minutes. The internal temperature should read 160 degrees F. Drain excess grease.

Cut the baked hamburger patty into 12 equal squares and place one patty onto each bun.

Top with American cheese and ketchup, pickles optional.