Heat the oil and saute the vegetables: In a large heavy pot or Dutch oven, heat 2 tablespoons extra virgin olive oil over medium-high heat until shimmering. Add the chopped onion, carrots, and garlic and cook, stirring frequently, for about 3 to 5 minutes or until the carrots have softened and the onions and garlic are fragrant.

Cook the sausage: Add in the Italian sausage and cook, stirring often for about 5 minutes or until the sausage is cooked. Carefully drain excess fat, particularly if you used pork sausage.

Add the liquids and seasonings: Add the tomato sauce, chicken broth, and Italian seasoning. Stir to combine. Raise the heat and allow the liquid to come to a boil.

Add the pasta and finish the soup: Add the tortellini pasta and cook according to package instructions (about 3 to5 minutes), then stir in the kale leaves. Turn the heat off. Add the flour to the milk and whisk well then slowly stir the mixture into the soup.

Serve: Ladle the soup into serving bowls and finish with grated Parmesan cheese and red pepper flakes to your liking. Serve immediately.