Bake the crust: Heat the oven to 350°F (175°C). Mix the crust ingredients, press into a parchment-lined 8 x 8-inch pan, and bake 10 to 12 minutes. Lower the oven to 325°F (165°C).
Whisk: Whisk the pumpkin, Greek yogurt, and maple syrup, then the eggs one at a time, then the cornstarch, spice, vanilla, and salt.
Bake: Pour over the crust and bake 38 to 45 minutes, until the edges are set and the center jiggles slightly.
Chill and slice: Cool 1 hour, chill at least 4 hours, then lift out and cut into 16 squares with a hot, dry knife.