Heat olive oil in large skillet over medium heat. Place ground beef into a large mixing bowl. Add Panko, Parmesan, salt, pepper, egg, milk, mustard and hot sauce. Gently mix until combined. Take 2 tablespoons of meatball mixture and roll into balls. In batches, add meatballs to hot skillet, browning all sides, about 5 minutes. Removed meatballs. Remove oil from skillet then add meatballs back to skillet over low heat.