01 - Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.
02 - In a skillet over medium heat, cook diced onion until translucent, about 3 minutes. Add ground beef, garlic powder, salt, and black pepper. Sauté until beef is fully browned, then drain excess fat.
03 - Stir in ketchup, mustard, Worcestershire sauce, and chopped pickles. Remove pan from heat and allow the mixture to cool slightly.
04 - Flatten each biscuit round on a clean surface. Place 1 tablespoon of the beef mixture and 1/2 tablespoon shredded cheddar cheese in the center of each biscuit. Top with one mozzarella cube.
05 - Bring biscuit edges together to seal fillings completely, forming a ball. Pinch seams to secure and set seam-side down on the lined baking sheet.
06 - Brush each dough ball lightly with beaten egg, then sprinkle with sesame seeds.
07 - Bake in preheated oven for 15 to 18 minutes, or until golden brown and cooked through.
08 - Allow bombs to cool for a few minutes before serving. Serve with extra dipping sauces if desired.