Preheat the oven to 375°F. Place the squash halves cut-side down on a parchment-lined baking sheet.
Brush with olive oil, then sprinkle with salt and pepper. Roast in the oven for 30 minutes.
Meanwhile, prepare the quiche filling. In a large bowl, whisk together the eggs, half-and-half, dry mustard, garlic powder, onion powder, and paprika until combined.
Stir in the Gruyere, cheddar, and chives.
When the squash is done roasting, reduce the oven temperature to 350°F. Place the prepared pie crust on a baking sheet.
Carefully scoop out the roasted squash and add it to the egg mixture. Stir until everything is combined.
Pour the mixture into the prepared pie crust. Bake in the oven for 40 minutes, or until the top is golden brown and a knife inserted in the center comes out clean.
Let cool for 10 minutes before serving.
Interesting Facts
Acorn squash is a winter squash that is native to Central and South America.
Gruyere cheese is a type of Swiss cheese that has a nutty flavor.
Quiches are a great way to get creative with vegetables and leftover ingredients.