Preheat a skillet over medium-high heat. In a large bowl, combine the ground beef, sweet onion, brown sugar, salt, and pepper. Mix well to combine, then portion into individual ½ cup balls. Place each ball on an 8x8 square piece of parchment.
Place each burger on the skillet, 1-2 at a time, parchment side up. Use a burger press to smash the burgers onto the skillet until they are ¼-½ inch thick. Sear for 2-3 minutes per side.
Assemble breakfast burgers by toasting everything bagels, adding cream cheese, your favorite crispy bacon, fried eggs or mashed avocado. Enjoy!