Preheat your oven to 375°F (190°C) and grease a medium baking dish.

Steam or blanch the diced carrots, parsnips, cauliflower, and Brussels sprouts for 3–4 minutes until tender, then drain.

In a large bowl, combine the prepared vegetables with cream of mushroom soup, milk, shredded cheese, thyme, garlic powder, salt, and pepper.

Spoon the vegetable mixture into the greased baking dish, spreading evenly.

In a separate bowl, mix breadcrumbs with melted butter and sprinkle over the vegetable mixture.

Bake uncovered for 25–30 minutes until the topping is golden brown.

Let the casserole rest for 5 minutes before serving.