Adjust rack to top position and preheat oven to 425 degrees. Wash and dry produce.

Trim and halve Brussels sprouts lengthwise. Trim and cut mushrooms into ¼-inch-thick slices (skip if your mushrooms are pre-sliced!). Trim scallions; cut whites into 1-inch pieces and thinly slice greens. Trim and discard woody bottom ends from asparagus; cut crosswise into 1-inch pieces. Zest and quarter lemon.

Toss Brussels sprouts, mushrooms, and scallion whites on a baking sheet with a large drizzle of oil, half the garlic powder, salt, and pepper. Roast on top rack for 5 minutes (you’ll add more to the sheet then).

In a medium bowl, toss asparagus with a drizzle of oil, remaining garlic powder, salt, and pepper.

Once veggies have roasted 5 minutes, remove sheet from oven. Carefully arrange asparagus over top. Return to top rack and roast until veggies are browned and tender, 12-15 minutes more.

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

Stir in half the Parmesan.

Whisk in cream cheese, sour cream, stock concentrates, and 1 TBSP butter (2 TBSP for 4). Bring to a simmer; cook, stirring occasionally, until thickened, 3-4 minutes. Taste and season with salt and pepper if desired. TIP: If polenta seems too thick, stir in a splash of water.

Once veggies are done, sprinkle with lemon zest; toss to combine. TIP: Be careful—baking sheet is hot!

Before serving, briefly stir polenta (rewarm over medium heat if necessary).

Divide polenta between bowls. Top with roasted veggies and a generous squeeze of lemon juice. Top with scallion greens, sunflower seeds, and remaining Parmesan. Serve.