Adjust rack to top position and preheat oven to 450 degrees. Bring a large pot of salted water to a boil. Wash and dry produce.

Halve, core, and thinly slice bell pepper. Trim and halve zucchini lengthwise; slice crosswise into ½-inch-thick half-moons. Trim and thinly slice scallions, separating whites from greens. Zest and quarter lemon.

Toss bell pepper and zucchini on a baking sheet with a drizzle of oil, salt, and pepper. Roast on top rack until tender and lightly charred, 15-18 minutes.

While veggies roast, rinse shrimp under cold water. Pat shrimp dry with paper towels; season with salt and pepper. Heat a drizzle of oil in a large pan over medium-high heat. Add shrimp or sausage; cook, stirring frequently, until cooked through, 4-6 minutes. Transfer to a plate.

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

Heat a drizzle of olive oil in pot used for pasta over medium heat. Add scallion whites and 1 tsp Tuscan Heat Spice (2 tsp for 4 servings); cook, stirring, 1 minute.

Whisk in cream sauce base, stock concentrate, and ¼ cup reserved pasta cooking water (½ cup for 4). Cook, whisking, until slightly thickened, 2-3 minutes.

Reduce heat to medium low and whisk in crème fraîche until smooth.

Add drained penne, peas, half the Parmesan (save the rest for serving), half the lemon zest, 1 TBSP butter (2 TBSP for 4 servings), and a big squeeze of lemon juice to pot with sauce. Cook, stirring, until butter has melted and penne is coated in a creamy sauce.

Stir in roasted veggies. Taste and season with salt and pepper. Add more lemon zest or lemon juice if you like.

Stir in shrimp or sausage along with roasted veggies.

Divide pasta between plates or shallow bowls. Top with scallion greens and remaining Parmesan. Serve with any remaining lemon wedges on the side.