Giant Mozzarella Stuffed Meatball Garlic Butter Sub

This is the ultimate meatball sub: four giant, juicy meatballs, each hiding a molten mozzarella core, simmered in rich marinara sauce, and piled into crusty sub rolls brushed with garlic herb butter.

A blanket of provolone is broiled until blistered and bubbling, and every pull reveals that endless cheese stretch. It's a showstopper dinner that feels like a special occasion but comes together in under an hour.

The idea is simple: take everything you love about a classic meatball sub and make it bigger, cheesier, and more dramatic. The meatballs are seasoned with parmesan, garlic, and Italian herbs, then stuffed with a cube of mozzarella.

They're seared until deeply browned, then simmered in marinara so they stay succulent. The rolls get a garlic butter toast, and a final blast under the broiler with provolone makes the whole thing irresistible.

Ingredients

Why this recipe works

The method of stuffing a cube of low-moisture mozzarella into the center of each meatball guarantees a dramatic cheese pull in every bite.

Low-moisture mozzarella melts slowly and holds its shape, so it stays inside the meatball during searing and simmering, then becomes molten when you cut into it. The breadcrumbs and egg bind the meat so the cheese doesn't leak out.

Simmering the meatballs in marinara after searing does double duty: the sauce picks up the browned bits from the pan, becoming richer, while the meatballs stay moist and absorb flavor.

Toasting the sub rolls with garlic butter creates a crisp barrier that keeps the bread from getting soggy, and broiling the provolone adds a bubbly, blistered finish that's both textural and visually stunning.

Notes and substitutions

Use 80% lean ground beef for the juiciest meatballs; leaner beef can turn dry. Low-moisture mozzarella is essential—fresh mozzarella contains too much water and will make the meatballs soggy or cause the cheese to burst out. For the garlic butter, use unsalted butter so you can control the salt level.

A cast-iron skillet is ideal for searing and simmering, but any heavy-bottomed skillet works. If you don't have provolone, use mozzarella or a blend of Italian cheeses. The sub rolls should be sturdy enough to hold the filling; choose bakery-style rolls with a crisp crust.

• ground beef: Ground turkey or ground chicken can replace beef; reduce cook time slightly and ensure internal temperature reaches 165°F.
• plain breadcrumbs: Use panko breadcrumbs for a lighter texture, or gluten-free breadcrumbs to make the dish gluten-free.
• low-moisture mozzarella: Fresh mozzarella works but will melt faster and may leak; pat it dry before cubing.
• marinara sauce: Use a smooth tomato sauce seasoned with basil and oregano if marinara is unavailable.

Equipment

• Large mixing bowl
• Cast-iron skillet or heavy skillet
• Baking sheet
• Aluminum foil
• Chef's knife
• Cutting board
• Wooden spoon
• Pastry brush