01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - Heat a skillet over medium heat. Sauté onion until translucent, about 3 minutes. Add ground beef, garlic powder, salt, and black pepper. Cook until beef is browned and crumbly, then drain excess fat.
03 - Stir in ketchup, yellow mustard, Worcestershire sauce, and chopped pickle. Mix thoroughly and remove from heat. Allow the filling to cool slightly.
04 - Flatten each biscuit round with your hands. Place 1 tablespoon beef mixture and 1/2 tablespoon shredded cheddar in the center of each. Top with a cube of mozzarella cheese.
05 - Gather dough around the fillings, pinching edges to seal and form a smooth ball. Position seam side down on the prepared baking sheet.
06 - Brush each assembled bomb with beaten egg and sprinkle the tops with sesame seeds.
07 - Bake for 15 to 18 minutes, or until the exterior is deep golden brown.
08 - Let bombs cool slightly before serving. Accompany with additional sauces if desired.