Step 1

Preheat the oven to 375 degrees F.

Step 2

Scatter the squash and onions on a rimmed baking sheet, drizzle with the olive oil and season with 1/2 teaspoon salt. Toss well to coat evenly.

Step 3

Roast until the squash is tender all the way through and the onions are soft and turning golden brown, 28 to 30 minutes. Let cool slightly.

Step 4

Unroll the pie crust onto a nonstick baking sheet. Crumble half of the cheese over the crust, leaving a 2-inch border. Top with the roasted onions and then shingle with the squash in circles. Fold the crust borders up and over the filling, crimping every 2 inches or so. Sprinkle the exposed squash with the pistachios and the remaining cheese.

Step 5

Bake until the crust is golden brown and the cheese is melted, about 30 minutes. Let cool for 5 minutes, then sprinkle with the arugula and pomegranate seeds.

Step 6

Slice and serve warm or at room temperature.