Step 1

Adjust rack to top position and preheat oven to 450 degrees. Bring a large pot of salted water to a boil. Wash and dry all produce. Halve, peel, and thinly slice onion. Trim and halve zucchini lengthwise; cut crosswise into ½-inch-thick half-moons.

Step 2

Toss zucchini on a baking sheet with a drizzle of oil, half the Tuscan Heat Spice, and a pinch of salt and pepper. Roast on top rack, tossing halfway through, until browned and tender, 14-16 minutes. Loosely cover with foil to keep warm.

Step 3

Once water is boiling, add gemelli to pot. Cook until al dente, 9-11 minutes. Reserve 1½ cups pasta cooking water (2 cups for 4 servings), then drain.

Step 4

Heat a drizzle of oil in a large pan over medium-high heat. Add onion and a pinch of salt and pepper. Cook, stirring occasionally, until softened, 5-6 minutes. Add sausage and cook, breaking up meat into pieces, until browned all over, 3-4 minutes (it’ll finish cooking in the next step).

Step 5

Add tomato paste and remaining Tuscan Heat Spice to pan. Cook, stirring constantly, until fragrant, 1-2 minutes. Stir in stock concentrate, 1 cup reserved pasta cooking water (1½ cups for 4 servings), and a big pinch of salt and pepper. Bring to a low simmer; cook until sauce is slightly thickened and sausage is cooked through, 2-3 minutes. Reduce heat under pan to medium low.

Step 6

Stir gemelli, zucchini, sour cream, and 1 TBSP butter (2 TBSP for 4 servings) into pan until thoroughly combined. (TIP: If needed, stir in more reserved pasta cooking water a splash at a time until pasta is coated in a creamy sauce.) Divide between bowls. Sprinkle with Parmesan.