To make this Marry Me Italian Sausage Soup, start by dicing the white onion and red bell pepper, mincing the garlic, and slicing the sun-dried tomatoes into thin strips.
Add 2 tablespoons of the oil from the sun-dried tomato jar to a large pot or Dutch oven on the stove over medium heat. Once the oil is shimmering, add the Italian sausage. Use a wooden spoon to break it into small pieces and cook for 5–6 minutes, until mostly browned and cooked through.
Next, add the diced onion, red bell pepper, and minced garlic to the pot. Stir well and sauté for about 4–5 minutes, until the vegetables have softened and become fragrant.
Pour in the chicken broth, then add the sliced sun-dried tomatoes, Italian seasoning, crushed red pepper flakes, and kosher salt. Stir to combine and bring the mixture to a gentle simmer.
Once simmering, add the dried pasta directly into the soup. Stir occasionally to prevent sticking and allow the pasta to cook for about 4–5 minutes.
Reduce the heat to low and stir in the heavy cream (or coconut milk), fresh spinach, and chopped basil. Continue to cook for another 3–4 minutes, until the spinach has wilted and the pasta is al dente.
Remove the pot from the heat and stir in the freshly grated parmesan cheese until melted and fully incorporated. Taste and adjust seasoning if needed.
Ladle into bowls, top with extra parmesan and fresh basil, and serve warm.