Salt and freshly ground black pepper
2 tablespoons extra-virgin olive oil (EVOO)
1 small onion, finely chopped
3 cloves garlic, chopped
1 teaspoon red pepper flakes
1 cup beef stock (eyeball it)
1 14-ounce can chunky-style crushed tomatoes
1 28-ounce can crushed tomatoes
4 1-inch thick slices (or equivalent) of leftover meatloaf
1 cup ricotta cheese
1 cup grated Parmigiano Reggiano, divided
1 ball fresh mozzarella cheese, cut into small cubes, divided
Preheat the oven to 375F.
Bring a large pot of water to a boil over high heat. Once the water comes to a boil, add a generous handful of salt. Cook the pasta just short of al dente. Drain and return to the pot.
Preheat a medium skillet over medium heat. Add EVOO, onions, garlic and red pepper flakes. Cook, stirring frequently, for about 5 minutes. Add the beef stock and both cans of crushed tomatoes, and bring to a bubble. Chop or crumble up leftover meatloaf and add to the sauce. Simmer for 3-4 minutes. Season with salt and pepper to taste.
Add half of the tomato meatloaf sauce to the cooked pasta. Add the ricotta and half of the Parmigiano, and toss to coat. Add half of the cubed mozzarella cheese, give everything a stir and then transfer it to an oven-safe baking dish.
Top with the remaining tomato meatloaf sauce, cubed mozzarella and the Parmigiano. Transfer to the oven and bake until the top is nice and brown, about 10-15 minutes.