01 - Preheat oven to 400°F (200°C) and line a baking sheet with parchment paper.
02 - Heat a skillet over medium heat. Cook the diced onion until translucent, about 3 minutes. Add ground beef, garlic powder, salt, and black pepper. Cook until beef is thoroughly browned and crumbly, then drain excess fat.
03 - Stir in ketchup, yellow mustard, Worcestershire sauce, and chopped pickles. Mix well and remove from heat. Let the mixture cool slightly so it is easier to handle.
04 - Flatten each biscuit round using your hands or a rolling pin. Place 1 tablespoon beef mixture and 1/2 tablespoon shredded cheddar cheese in the center of each round. Add 1 mozzarella cube to each.
05 - Carefully fold the dough around the fillings, pinching the seams to seal completely and shaping each into a ball. Place seam side down on the prepared baking sheet.
06 - Brush each dough ball with beaten egg and sprinkle with sesame seeds for a glossy, flavorful finish.
07 - Bake in the preheated oven for 15 to 18 minutes or until the bombs are puffed and golden brown on top.
08 - Allow to cool on the baking sheet for several minutes before serving. Present with assorted burger sauces for dipping if desired.