Heat broiler to high. Bring a large pot of salted water to a boil. Wash and dry produce.

Meanwhile, heat a drizzle of olive oil in a large pan over medium-high heat. Add chicken sausage and remaining Italian Seasoning. Cook, breaking up meat into pieces, until browned and cooked through, 4-6 minutes.

Once water is boiling, add spaghetti to pot. Cook until al dente, 9-11 minutes. Reserve ½ cup pasta cooking water, then drain and set aside.

While pasta cooks, stir crushed tomatoes, stock concentrate, and 1 tsp sugar into pan with sausage. Season generously with salt and pepper. Bring to a simmer and cook until reduced, 5-7 minutes.

Stir sour cream and 1 TBSP butter into pan with sauce. Add drained spaghetti and zucchini; toss to coat. If needed, stir in reserved pasta cooking water 1 TBSP at a time until pasta is thoroughly coated in sauce. Taste and season with salt and pepper.

Divide pasta between bowls. Sprinkle with Parmesan and serve.