Boil a large pot of salted water and cook spaghetti according to package instructions until al dente. Reserve 1 cup pasta water, then drain.

Heat olive oil in a skillet over medium heat. Add sun-dried tomatoes and sauté for 2 minutes until softened.

Add minced garlic and red pepper flakes (optional) to the skillet. Sauté for 30 seconds until fragrant.

Reduce heat to low, pour in half-and-half or heavy cream, and let the sauce thicken for 3-4 minutes.

Stir in fresh spinach until wilted, about 2-3 minutes.

Incorporate grated Parmesan cheese until melted, adding reserved pasta water as needed for consistency.

Toss drained spaghetti in the sauce until coated.

Fold in chopped basil and serve, garnishing with extra Parmesan if desired.