Step 1: Prepare the zucchini. Grate the zucchini finely and place it in a clean kitchen towel or paper towels. Squeeze out as much liquid as possible. This step is crucial for perfectly textured meatballs for your Sneaky Zucchini Meatball Subs with Mozzarella.
Step 2: Mix the meatballs. In a large bowl, combine the squeezed zucchini, ground beef, ground pork, breadcrumbs, Parmesan cheese, egg, minced garlic, parsley, oregano, salt, and pepper. Use your hands to gently mix until just combined. Be careful not to overmix, as this can make the meatballs tough. The goal is tender meatballs for your Sneaky Zucchini Meatball Subs with Mozzarella.
Step 3: Form the meatballs. Roll the mixture into approximately 18-20 meatballs, about 1.5 inches in diameter. Arrange them on a plate.
Step 4: Brown the meatballs. Heat the olive oil in a large, deep skillet or Dutch oven over medium-high heat. Add the meatballs in batches, being careful not to overcrowd the pan. Brown them on all sides, about 5-7 minutes per batch. They don't need to be cooked through, just nicely browned. Remove the browned meatballs and set aside.
Step 5: Simmer the sauce. Reduce the heat to medium-low. If there's excess grease in the pan, you can drain some of it. Pour in the marinara sauce and bring it to a gentle simmer. Carefully add the browned meatballs back into the sauce. Ensure they are mostly submerged. Cover and simmer for at least 30 minutes, or up to an hour, allowing the flavors to meld and the meatballs to cook through. This slow simmer makes your Sneaky Zucchini Meatball Subs with Mozzarella truly shine.
Step 6: Prepare the rolls. Preheat your oven to 375°F (190°C). Brush the insides of the hoagie rolls with melted butter. Place them butter-side up on a baking sheet and toast in the oven for 3-5 minutes, or until lightly golden. This creates a sturdy base for your Sneaky Zucchini Meatball Subs with Mozzarella.
Step 7: Assemble and bake. Carefully fill each toasted roll with 3-4 meatballs and a generous amount of sauce. Top generously with slices or torn pieces of fresh mozzarella cheese. Return the filled subs to the baking sheet.
Step 8: Final bake. Bake for another 8-12 minutes, or until the mozzarella is melted, bubbly, and lightly golden. This final step brings together all the delicious elements of your Sneaky Zucchini Meatball Subs with Mozzarella.
Step 9: Serve. Garnish with a sprinkle of fresh parsley or additional Parmesan cheese, if desired. Serve immediately and enjoy your hearty Sneaky Zucchini Meatball Subs with Mozzarella!