Preheat oven to 400°F (200°C).

In a large bowl, toss butternut squash, carrots, Brussels sprouts, onion, and garlic with olive oil, thyme, rosemary, salt, and pepper.

Spread the vegetables on a baking sheet and roast for 25-30 minutes until tender.

In a saucepan, heat vegetable broth to a simmer.

If you want a thicker filling, mix cornstarch with a little cold water and add it to the broth, stirring until thickened.

Combine the roasted vegetables with the broth in a large bowl.

Roll out the pastry dough and cut into circles to fit your pie dishes.

Fill each pastry with the vegetable mixture and cover with another piece of pastry.

Seal edges and brush with egg wash if desired.

Bake for 25-30 minutes until golden brown.