Preheat the oven to 400ºF. Spray a baking sheet with the cooking spray.

Arrange the squash in a single layer on the baking sheet and spray with more cooking spray. Roast until tender, tossing halfway through, 18-20 minutes total. Set aside.

Heat a medium skillet over medium heat. Add the prosciutto and cook, stirring, until it begins to crisp, 6-8 minutes. Transfer to a paper towel–lined plate.

Line a second baking sheet with parchment paper. Place the pizza dough on the lined pan and press it out with floured hands or a rolling pin until it’s about ¼-inch thick (don’t worry about the shape).

Spray the pizza dough lightly with cooking spray. Top the pizza with the cheese, pears, crispy prosciutto, and roasted squash.

Bake until the crust has turned a light golden brown, 12-15 minutes. The bottom of the pizza should be crisp and brown—to check it, you can carefully lift it using a large spatula, then tap it.

Top the pizza with arugula, if desired, and enjoy immediately.