How to Make a Juicy Homemade Burger in the Oven. Preheat the oven to 4. F. Wash your hands. Combine a 14 lb. Mix together and form a ball, which should be about the size of a golf ball. Flatten the ball into a patty less than 12 inch thick. Usually the thinner the patty, the less chance of overcooking and drying out the exterior. Spray a baking pan with nonstick cooking spray. Place the pan in the oven 5 minutes before using. Heating the pan before the patty touches it will sear the patty quickly, locking in the juices. Place the patty on the baking pan, using the cooking tongs. Bake the patty for 5 minutes. After 5 minutes, juices will start to appear on the surface of the patty. This is a good indication that the inside of the patty is being cooked. Pull the pan out of the oven with oven mitts. Flip the patty with cooking tongs. Add 14 cup each of diced green pepper and chopped onion to the surface of the patty. Return the pan to the oven. Bake for an additional 5 to 1. Stick a meat thermometer into the center of the patty. Make Ahead Scalloped Potatoes. Make sure it reads a minimum internal temperature of 1. F. Nonstick cooking spray. Baking pan. 14 lb. Cooking tongs. Oven mitts. Meat thermometer. The most popular additions to a burger, after salt and pepper, are chopped onion and garlic powder. If you refrigerate the patty, keep at 4. F or below and use within 2 days. Never leave ground beef out at room temperature for more than 2 hours. Best 2. 5 Baked hamburgers ideas on Pinterest.