Sheet Pan Meatball Parm Sandwiches

Preheat the oven to 425°F.  

For the cheater focaccia, follow the package directions to prepare the dough. Generously grease a 9-by-13-inch sheet pan with EVOO. Put the dough in the pan and press it into an even layer that covers the bottom. Oil your fingers and gently press into the dough to dimple it. Drizzle the top with a little more EVOO. 

Bake until the focaccia is golden brown and cooked through, about 20 to 25 minutes, or follow the package instructions. 

When the focaccia is almost ready, in a small saucepan, melt the butter over low heat, then grate in the garlic. Brush the baked focaccia with the garlic butter and sprinkle with flaky seas salt. 

While the focaccia bakes, make the meatballs. Line a 9-by-13-inch sheet pan with aluminum foil and set aside.  

Heat a large skillet over medium heat. Add the olive oil and when it shimmers, add the onions and a large pinch of salt and pepper. Cook, stirring occasionally, until the onions are soft and translucent, but not browned, about 10 minutes. Add the garlic and red pepper flakes and cook, stirring occasionally, for about 2 minutes more. Remove from the heat and allow the onion mixture to cool.  

In a large bowl, add the meatball mix, cooled onion mixture, eggs, milk, breadcrumbs, ¾ cup of the Parmigiano and the parsley. Season with a healthy pinch of salt and pepper and mix until thoroughly combined, but be careful not to overmix. 

Transfer the meat mixture to the prepared sheet pan and spread it in an even layer that covers the bottom. Bake until the internal temperature reaches 165°F, 25 to 30 minutes. Remove from the oven and turn on the broiler. Carefully tip one corner of the sheet pan over a heatproof dish and allow any rendered fat or liquid to drain off. 

Spread the marinara sauce evenly over the meatball mixture, then top with the mozzarella and remaining ¼ cup Parmigiano. Broil until the cheese is bubbly and lightly browned, 3 to 5 minutes. Let cool a few minutes, then garnish with basil. 

To serve, cut the focaccia into slices as desired and then cut each slice crosswise into top and bottom pieces. Cut the meatball Parm into similarly sized portions and sandwich between the top and bottom pieces of bread.