roasted winter vegetables with cheesy polenta

4 cups cauliflower florets
(see tip in the notes)
4 cups butternut squash
peeled and cubed into 1- to 1.5-inch cubes
1 whole onion
2 tbsp extra-virgin olive oil
1/2 tsp garlic powder
3/4 tsp freshly ground pepper
1/4 tsp salt
2 1/2 cups vegetable broth
or reduced-sodium chicken broth
1 cup water
3/4 cup cornmeal
1 tsp fresh rosemary
chopped or 0.5 teaspoon dried
2/3 cup parmesan cheese
finely shredded, preferably parmigiano-reggiano
Preheat oven to 500°F.
Toss cauliflower, squash and onion in a large bowl with oil, garlic powder, 1/2 teaspoon pepper and salt. Spread on a rimmed baking sheet. Roast, stirring once, until tender and browned in spots, 25 to 30 minutes.
Meanwhile, combine broth and water in a small saucepan. Bring to a boil.
Slowly whisk in cornmeal, rosemary and the remaining 1/4 teaspoon pepper until smooth. Reduce heat to low, cover and cook, stirring occasionally, until very thick and creamy, 10 to 15 minutes. Stir in cheese; remove the polenta from the heat.
Serve the vegetables over the polenta.
Tip: To prepare florets from a whole head of cauliflower, remove outer leaves. Slice off the thick stem. With the head upside down and holding a knife at a 45° angle, slice into the smaller stems with a circular motion—removing a “plug” from the center of the head. Break or cut florets into the desired size. To store, refrigerate in a plastic bag for up to 5 days.