Cook the Pasta:

• Bring a large pot of salted water to a boil.
• Add the pasta and cook according to the package instructions until al dente.
• Reserve 1 cup of pasta water, drain, and set the pasta aside.

Sauté the Vegetables:

• In a large skillet, heat 2 tablespoons of olive oil over medium heat.
• Add the minced red onion and sauté for 3-4 minutes until softened.
• Stir in the lightly crushed garlic clove and cook for an additional 1-2 minutes, until fragrant.

Cook the Mushrooms:

• Add the halved mushrooms to the skillet.
• Cook for 5-7 minutes, stirring occasionally, until they release their moisture and begin to brown.

Wilt the Spinach:

• Add the spinach leaves to the skillet and cook for 2-3 minutes, stirring, until they wilt and combine with the mushrooms.

Make the Creamy Sauce:

• Reduce the heat to low and stir in the crème fraîche.
• Let it warm through and coat the vegetables, creating a creamy sauce.
• Stir in the grated cheddar cheese until melted and smooth.

Combine and Serve:

• Add the cooked pasta to the skillet with the sauce and toss until evenly coated.
• If the sauce feels too thick, gradually add the reserved pasta water until the desired consistency is reached.
• Season with sea salt and black pepper to taste.
• Serve immediately, garnished with extra cheddar cheese if desired.