01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - In a skillet over medium heat, cook the onion until translucent, about 3 minutes. Add ground beef, garlic powder, salt, and pepper. Cook until beef is browned, then drain excess fat.
03 - Stir in ketchup, yellow mustard, Worcestershire sauce, and chopped pickles. Remove skillet from heat and allow mixture to cool slightly.
04 - Flatten each biscuit round. Place 1 tablespoon of beef mixture and 1/2 tablespoon shredded cheddar in the center. Top with a mozzarella cheese cube.
05 - Fold dough around the filling, pinching edges to seal completely into a ball. Place each ball seam side down on the prepared baking sheet.
06 - Brush each dough ball with beaten egg and sprinkle with sesame seeds for a classic burger finish.
07 - Bake in the preheated oven for 15 to 18 minutes, or until golden brown.
08 - Allow bombs to cool slightly before serving. Serve warm with your choice of dipping sauces.