Stick Stuffed Crust Mozzarella Pizza

Ingredients
Pizza:
1 pound of cooked pizza dough
2 tablespoons of olive oil
2 tablespoons unsalted butter at room temperature
60 slices pepperoni (from a 6 ounce package)
8 mozzarella string cheese sticks
2 tablespoons grated Parmesan, plus more to serve
meat sauce:
1 tablespoon of olive oil
1 sweet Italian sausage link, housing removed (about 1/4 pound)
1 clove garlic, finely chopped
A half red pepper, finely chopped
Half a small onion, finely chopped
1/4 cup tomato paste
Pinch crushed red pepper flakes
Kosher salt and freshly ground black pepper

Directions
Special equipment: a metal 8-by-8 inch baking mold

For the pizza: Put the pizza dough into a large bowl and coat with the oil. Cover the dish with plastic film and leave it in a warm place until a little swollen and at room temperature, about 30 minutes.

Spread the butter all the way inside a metal 8-by-8 inch baking tray and place the dough in the middle. Starting from the center of the dough, and with the fingertips, slide the dough onto the corners of the pan and all the way to the sides.

Make a pepperoni edge (slightly overlapping the meat) around the bottom edge of the dough (about 8 pepperoni per side). Place 1 cheese stick on the pepperoni on each side, then fold the dough out the edges of the pan to cover it. Slice the dough with the pepperoni and cheese inside back firmly against the sides of the pan. Stir the dough around the pepperoni and cheese by squeezing the dough and pinching it. You now have a stuffed crust. Cover the dough in the bottom of the pan (but not the crust) with the remaining pepperoni.

Pull each of the remaining 4 cheese bars into 4 long pieces. Place half of the cheese pieces evenly on the crust along the edges of the dough so they touch the sides of the pan. Put the remaining pieces of cheese over the pepperoni in the middle. Sprinkle the whole pizza with Parmesan. Cover with plastic film and store in a warm place until it slept, about 30 minutes.

Place an oven rack in the lower third of the oven, place a baking tray on the rack, and set the oven to 500 degrees F. Place the pizza on the preheated baking tray and bake until the edges are dark golden and the cheese is melted and bubbly, 15 to 20 minutes.

Meanwhile, make the meat sauce: Heat the oil in a small saucepan over medium heat until shimmering. Add the sausage and boil, break it with a wooden spoon until slightly browned, about 4 minutes. Add garlic, pepper and onion and boil, stirring occasionally, until the moisture from the pan is evaporated and the onion is soft, about 3 minutes. Add the tomato paste, 3/4 cup of water, a pinch of each red pepper flakes and salt and several loops of black pepper. Bring to the boil, reduce the heat to medium-low and cook, uncovered, stirring often until thick, about 5 minutes.

Remove the pizza from the oven and loosen the sides and floors from the pan with a metal spatula. Slice the pizza on a cutting board and spoon the sauce in the middle of the pizza. Sprinkle with Parmesan and cut into the squares.