Once water is boiling, add spaghetti to pot. Cook until al dente, 9-11 minutes, then drain and set aside. To pan with veggies, add crushed tomatoes, stock concentrate, ¼ cup water, remaining Tuscan Heat Spice, ½ tsp sugar (1 tsp for 4 servings), salt, and pepper. Bring to a boil, then reduce heat to medium. Cook until slightly thickened, 8-10 minutes. Stir in meatballs. Cook until sauce is very thick, 2-3 minutes more.