Preheat your oven to 400°F (200°C).

In a large mixing bowl, combine butternut squash, carrots, parsnips, sweet potatoes, and Brussels sprouts. Drizzle with olive oil and sprinkle with salt, pepper, thyme, and rosemary. Toss until well-coated.

Spread seasoned vegetables evenly on a baking sheet in a single layer. Roast for 25-30 minutes, stirring halfway through, until tender and lightly caramelized.

Melt butter in a saucepan over medium heat. Add chopped onion and minced garlic, stirring until the onion is translucent, about 3-5 minutes.

Stir in all-purpose flour with the onions and garlic to form a roux. Cook for 1-2 minutes until slightly golden.

Gradually whisk in vegetable broth and simmer for 3-4 minutes until thickened and smooth.

Gently fold the roasted vegetables into the thickened sauce. Add heavy cream and stir to combine. Adjust seasoning with salt and pepper.

On a floured surface, roll out puff pastry. Cut into shapes to cover the tops of your ramekins or baking dish.

Spoon the roasted vegetable and sauce mixture into ramekins. Place pastry rounds on top, sealing the edges gently.

Brush tops with beaten egg wash for a golden finish. Alternatively, use dairy-free milk for a vegan option.

Bake in the oven for 20-25 minutes until the puff pastry is golden brown and flaky.

Let the pot pies cool for 5-10 minutes before serving.