Step 1: Cook the Pasta

1. Bring a large pot of salted water to a boil.
2. Add the spaghetti and cook according to the package instructions until it’s al dente.
3. In the last 2 minutes of cooking, toss in the fresh spinach leaves to wilt them.
4. Drain the pasta and spinach together and set them aside.

Step 2: Sauté the Aromatics

1. Heat 1-2 tablespoons of the reserved sun-dried tomato oil in a large skillet over medium heat.
2. Add the finely chopped red onion and sauté for 3-4 minutes, or until softened.
3. Stir in the minced garlic and crushed red pepper flakes. Cook for an additional 1-2 minutes until fragrant.

Step 3: Add the Tomatoes and Broth

1. Stir in the chopped sun-dried tomatoes and cook for 1-2 minutes to release their flavors.
2. Pour in the broth (vegetable or chicken) and stir to combine.
3. Bring the mixture to a gentle simmer and let it cook for about 5 minutes, allowing the flavors to meld and the broth to reduce slightly.

Step 4: Incorporate the Cream and Cheese

1. Reduce the heat to low.
2. Stir in the sour cream and grated Parmesan cheese, mixing until the sauce becomes smooth and creamy.
3. Season with salt and black pepper to taste.

Step 5: Combine Pasta and Sauce

1. Add the cooked spaghetti and spinach to the skillet with the creamy tomato sauce.
2. Toss everything together until the pasta is fully coated in the sauce.

Step 6: Finish with Butter and Serve

1. Stir in 2 tablespoons of butter for a glossy finish.
2. Serve immediately, garnished with additional Parmesan cheese or a sprinkle of crushed red pepper flakes for extra heat if desired.