Heat the butter in a pan over a medium heat. Mix the onion and garlic powder, and cook for about 10 minutes until softened. Pour everything into a large bowl. Stir in the minced beef and pork, cheddar and breadcrumbs. Beat 3 eggs and combine them with the meat mixture. Season with salt and pepper. Make golf ball-sized spheres out of the meat mixture. Heat the oil in a pan over medium heat. Spread the remaining breadcrumbs onto a plate. In a large bowl, beat 1 egg and stir in the water. Dip the meatballs into the egg mixture, then roll them in the breadcrumbs. Carefully place the meatballs in the hot oil and fry until browned. Add the Vilnius Naminis mayonnaise and Vilnius Naminis pomidorų padažas.