Bring a large pot of salted water to a boil. Wash and dry all produce. Halve, peel, and thinly slice onion. Core, deseed, and thinly slice bell pepper. Mince parsley. Remove sausage from casings; discard casings.

Heat a large drizzle of oil in a large pan over medium-high heat. Add onion, bell pepper, and half the Tuscan Heat Spice. Cook, stirring, until slightly softened, 3-4 minutes. (For 4 servings, transfer veggies to a large bowl at this point. We want to ensure your sausage browns evenly!)

Add sausage and another drizzle of oil to pan. Cook, breaking up meat into pieces, until sausage is browned and cooked through, about 5 minutes.

Once water boils, add spaghetti to pot. Cook, stirring occasionally, until al dente, 9-11 minutes. Carefully scoop out and reserve 1 cup pasta cooking water (2 cups for 4 servings), then drain. Leave pot on stove.

Meanwhile, stir tomatoes into pan with sausage. Season with salt, pepper, and remaining Tuscan Heat Spice. Bring to a boil, then lower heat and let simmer while pasta cooks. After you’ve drained pasta, stir ¾ cup reserved cooking water (1 ¼ cups for 4 servings) and stock concentrate into pan. Continue simmering until slightly reduced, 1-2 minutes (3-4 minutes for 4 servings). Turn off heat.

Transfer sauce to pot used to cook pasta. Add spaghetti (and veggies for 4 servings) to pot, tossing to coat. (TIP: Add more pasta cooking water if needed to give sauce a loose consistency.) Stir in 1 TBSP butter (2 TBSP for 4 servings), half the parsley, and half the Parmesan. Season with salt and pepper. Divide between bowls, then sprinkle with remaining parsley and Parmesan.