Preheat your oven to 400°F. While it heats, combine the softened butter, mayonnaise, finely grated Parmesan, grated garlic cloves, red pepper flakes, and fresh parsley in a small bowl, mixing until smooth and evenly combined. This garlic butter spread is the foundation of authentic garlic bread flavor, so I like to make sure the garlic is well distributed throughout rather than having clumps.

In a large mixing bowl, combine the ricotta, eggs, minced garlic, kosher salt, black pepper, and dried oregano. Add the ground beef and breadcrumbs, folding gently with your hands until just combined—avoid overmixing or the meatballs will become dense. Form the mixture into 55-70 golf ball-sized meatballs and place them on parchment-lined baking sheets. Bake for 20-25 minutes at 400°F until cooked through and lightly browned on the edges. I find using an ice cream scoop helps make uniformly sized meatballs that cook evenly.

Slice the hoagie rolls in half lengthwise and place them cut-side up on a baking sheet. Generously spread the garlic butter mixture from Step 1 on the cut sides of each roll, making sure to coat them evenly. Bake at 400°F for 10-12 minutes until the rolls are golden brown and the garlic butter is bubbling at the edges. The rolls should be crispy on the outside but still soft enough to hold the meatballs without falling apart.

Remove the meatballs from the oven and transfer them to a mixing bowl. Pour the marinara sauce over the cooked meatballs from Step 2 and gently toss until each meatball is evenly coated. Remove the garlic bread rolls from the oven and spoon the sauced meatballs into each roll, dividing them equally—about 14-17 meatballs per sub depending on size. Top each filled roll with shredded mozzarella cheese, distributing it evenly.

Return the assembled subs to the 400°F oven and bake for 10 minutes until the mozzarella is melted and slightly browned. Remove from the oven and let cool for 2-3 minutes so the cheese sets slightly and the subs are easier to handle. Top each sub with a sprinkle of fresh parsley and extra Parmesan cheese for a vibrant finish and added flavor.