1 small butternut squash (about 2 pounds), halved lengthwise
1 tablespoon olive oil
1 large red onion, halved lengthwise and thinly sliced
5 cups baby spinach leaves (about 5 ounces)
1 pound fresh whole wheat pizza dough, at room temperature
4 ounces fontina cheese, grated (about 1 cup)
2 tablespoons pine nuts, toasted

1. Heat the oven to 400F. Coat a baking sheet with cooking spray. Scoop out
the squash seeds and spray the flesh with cooking spray. Place on the
prepared baking sheet flesh side down. Roast until golden brown, 30 to 35
minutes. Turn flesh side up and roast until tender when pierced with a fork, 20
to 25 minutes longer. When cool, scrape the flesh into a medium bowl and
mash. Season to taste with salt and freshly ground black pepper.

2. Place a pizza stone on a rack in the center of the oven and raise the
temperature to 550F. Heat the oil in a large skillet on medium-low heat. Add
the onion and cook, stirring occasionally, until tender and lightly browned, 20
to 25 minutes. Season to taste with salt and freshly ground black pepper.
Transfer to a bowl. Raise the heat to medium and coat the skillet with cooking
spray. Cook the spinach, stirring frequently, until wilted, 2 to 3 minutes.

3. Lightly flour the dough and roll into a 12″ circle, 1/8″ to 1/4″ thick, on
parchment paper. Spread about 1 1/2 cups squash over the dough. Top with
the onion and spinach. Transfer the pizza to the oven using a pizza peel or
large cutting board, sliding the parchment directly onto the pizza stone (the
peel or board does not go into the oven). Bake until the edges are lightly
browned, 7 to 9 minutes. Carefully pull out the rack with the pizza stone and
top the pizza with the cheese and pine nuts. Bake until the cheese is melted,
about 1 minute. Rest 5 minutes, cut into 8 pieces, and serve.