Soak spinach leaves in the sink with cold water, rinse and repeat until clean.

Spin in a salad spinner or pat dry with paper towels to remove excess moisture.

Heat olive oil in a large skillet on medium-high.

Add garlic and sauté until it starts to brown (about 1 minute).

Add spinach to skillet and gently toss with oil, garlic, and a pinch of salt and pepper until evenly coated.

Cover the pan, and cook until spinach is wilted (about 1 minute).

Mix again. Cover the pan and continue to cook for 1 minute.

Remove from heat, and set aside.

Cook pasta following instructions on the back of the box. Reserve 1 cup pasta water.

In a food processor (or blender), add ½ c of pasta water, cooked spinach, and parmesan and puree until the sauce is smooth. (Add more pasta water as needed to desired thickness)

Add the spinach sauce back to the pan over medium-high heat, and heat through.

Pour in more water if needed and season with salt and pepper.

Plate pasta and pour ½ c spinach sauce over noodles. Top with parmesan or red pepper flakes.