Heat olive oil in a large pot over medium-high heat. Add pancetta, if using, and cook until slightly crisp, about 5 minutes.
Add onion and garlic to the pot, reduce heat, and sauté for 5 minutes. Stir in crushed red pepper flakes and tomato paste, cooking for 2 minutes more.
Add tomato sauce, crushed tomatoes, and salt. Simmer the sauce for 20 to 30 minutes.
Cook ziti pasta according to package instructions. Once cooked, toss pasta with about two-thirds of the tomato sauce, reserving the rest for later.
Mix mascarpone with grated garlic and a pinch of salt. Preheat oven to 400°F.
In a 9×13 baking dish, layer half of the sauced pasta, dollops of mascarpone, half the mozzarella, and half the provolone cheeses. Add about a cup of the reserved tomato sauce.
Top with the remaining sauced pasta and the rest of the mozzarella and provolone cheeses. Spoon the remaining sauce around the edges.
Bake in the preheated oven for 20 minutes or until the dish is bubbly.
Optionally top with freshly grated Parmesan, fresh basil, or black pepper before serving.