01 - Set oven to 400°F and line a baking sheet with parchment paper.
02 - In a skillet over medium heat, cook the onion for about 3 minutes until translucent. Add the ground beef, garlic powder, salt, and pepper. Continue cooking until the beef is browned, then drain excess fat.
03 - Add ketchup, yellow mustard, Worcestershire sauce, and pickles to the beef mixture. Stir to combine and remove from heat. Allow to cool slightly.
04 - Flatten each biscuit into a round disc. Place 1 tablespoon of the cooked beef mixture and 1/2 tablespoon shredded cheddar in the center, then top with a mozzarella cube.
05 - Gather edges of the dough around the filling and pinch to seal, forming a ball. Arrange seam side down on the prepared baking sheet.
06 - Brush each assembled bomb with beaten egg and sprinkle with sesame seeds.
07 - Bake in the preheated oven for 15 to 18 minutes, or until the surface is golden brown.
08 - Allow to cool for a few minutes before serving. Enjoy alongside extra burger sauces if desired.