Pesto Pizza with Spaghetti Squash Crust

Preheat oven to 450 degrees F. Line a baking sheet with parchment paper; coat with cooking spray.

Cut squash in half lengthwise; scoop out and discard seeds. Place squash, cut sides down, on prepared baking sheet. Bake in preheated oven until very tender when pierced with a knife, 30 to 35 minutes. Remove from oven. Position oven rack in lowest position (do not turn oven off). Let squash cool to room temperature, 20 to 30 minutes. Re-line baking sheet with a clean sheet of parchment paper.

Scrape flesh from squash into a large bowl using a fork; discard squash shells. Place squash flesh in the center of a clean towel; squeeze squash dry and return to bowl. Add cornstarch and egg; using your hands, combine mixture until evenly and thoroughly incorporated. Press mixture into 4 (7-inch) rounds (about 1/8-inch thick) on prepared baking sheet. Bake at 450 degrees F on bottom rack of oven until rounds are dried in centers and lightly caramelized around edges, about 15 minutes. Remove from oven.

Top squash "pizzas" evenly with marinara and cheese. Return to oven; bake at 450 degrees F until cheese is melted and bubbly, 5 to 6 minutes. Drizzle evenly with pesto; sprinkle with basil.