Step 1

Prep: Slice 3/4 (~12 ounces) of the mushrooms into thin slices. Chop the remaining mushrooms (4 ounces, about 4 mushrooms) into a rough dice.

Step 2

Cook the Pasta: Bring a large pot of water to a boil. Add 2 teaspoons of salt and the pasta; cook until al dente according to package instructions. Remove 1 cup (235 ml) of pasta water from pot, then drain the pasta and set aside

Step 3

Sauté: In the meantime, warm the oil in a large pan over medium heat. Add the shallot and sauté for 3 to 5 min, until translucent. Add the diced mushrooms and sliced mushrooms to the pan and quickly mix to coat in oil, then spread the mushrooms out evenly across the bottom of the pan. Leave the mushrooms alone for 5 minutes to let them sear, then sprinkle the remaining salt on top and mix well. Sauté for another 5 to 7 minutes, until the mushrooms have released most of their liquid.

Step 4

Deglaze: Add the garlic and red pepper flakes (if using) to the pan and sauté for 1 to 2 minutes. Deglaze the pan with white win and sauté for an additional 1 to 2 minutes (if not using wine, skip this step)

Step 5

Combine: Add 1/2 cup (120 ml) of the reserved pasta to the pan and bring it to a simmer. Add the parmesan and spinach and mix well; continue to cook until the spinach has wilted, stirring occasionally. Fold in the pasta and season with additional salt or pepper to taste, as desired. If the sauce is too thick you can thin it out with additional pasta water.

Step 6

Serve: Serve warm and top as desired. Store leftovers in the refrigerator in an airtight container for up to 5 days.