Adjust rack to top position (top and middle positions for 4 servings) and preheat oven to 425 degrees. Wash and dry produce.

Cut cauliflower into bite-size pieces if necessary. Trim, peel, and cut carrots on a diagonal into ½-inch-thick pieces. Halve, peel, and cut onion into ½-inch-thick wedges. Halve tomato; cut into ½-inch-thick wedges. Peel and mince or grate garlic. Zest and quarter lemon.

On a baking sheet, toss cauliflower, carrots, onion, tomato, and garlic with a large drizzle of oil, half the Tuscan Heat Spice (all for 4 servings), salt, and pepper. (For 4, toss as instructed, then divide between two baking sheets.)

Roast on top rack until browned and tender, 20-25 minutes. (For 4, roast on top and middle racks, swapping rack positions halfway through cooking.)

Meanwhile, in a small pot, combine polenta and ⅓ cup water (⅔ cup for 4 servings) over medium heat. Mash with a potato masher until mostly smooth, 30-60 seconds.

Add sour cream, cream cheese, stock concentrate, half the Parmesan, and 1 TBSP butter (2 TBSP for 4).

Whisk until cheese melts and polenta is simmering and thickened, 2-3 minutes more. Season with salt and pepper to taste. Keep covered off heat until ready to serve.

Once veggies are done roasting, carefully add juice from half the lemon (whole lemon for 4 servings) and lemon zest to taste; toss to combine. Taste and season with salt and pepper if needed.

Before serving, briefly stir polenta (rewarm over medium heat if necessary). TIP: If polenta seems too thick, stir in a splash of water.

Divide polenta between shallow bowls and top with roasted veggies. Drizzle with olive oil and sprinkle with remaining Parmesan. Serve with any remaining lemon wedges on the side.