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