01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - In a large bowl, combine ground beef, breadcrumbs, Parmesan, egg, minced garlic, parsley, oregano, salt, and pepper. Mix until just combined; do not overwork.
03 - Shape mixture into 24 small meatballs, about 1 inch in diameter. Place on prepared baking sheet.
04 - Bake meatballs for 15 to 18 minutes, until browned and cooked through.
05 - Toss bread cubes with olive oil and garlic powder. Arrange on separate baking sheet and toast in oven for 6 to 8 minutes, turning once, until golden and crisp.
06 - Warm marinara sauce in small saucepan over low heat.
07 - Thread one toasted bread cube, one meatball, a mozzarella ball, and another bread cube onto each skewer.
08 - Arrange skewers on serving platter. Drizzle with melted butter and sprinkle with fresh basil. Serve warm with extra marinara sauce for dipping.