Begin by bringing a large pot of salted water to a boil. Add pasta and cook according to package instructions until al dente, about 8-10 minutes. Drain, reserving a cup of pasta water, set aside.

In a large skillet, heat 2 tablespoons of olive oil over medium heat. Add chopped onion and sauté for 2-3 minutes until translucent. Remove and set aside.

Add 1 tablespoon of olive oil to the skillet, add sliced mushrooms and sauté for about 3 minutes until golden brown. Remove and set aside.

Add fresh spinach to the same skillet and cook over medium heat for 2 minutes until wilted. Remove and set aside.

Sauté minced garlic in the skillet for about 30 seconds until fragrant. Deglaze with vegetable broth, scraping flavorful bits off the bottom.

Add heavy cream, grated Parmesan, chili flakes, and Italian seasoning to the skillet with the broth. Stir over medium heat for about 2 minutes until thickened.

Add the drained pasta back to the skillet along with the sautéed onions, mushrooms, and spinach. Stir to coat the pasta in the sauce, adding reserved pasta water as needed.

Taste and adjust seasoning if necessary, serve hot with extra grated Parmesan.