In a large pot, bring salted water to a boil and add your preferred pasta. Cook according to package instructions until al dente, about 8-10 minutes. Reserve 1 cup of pasta water, then drain and set pasta aside.

In a large skillet over medium heat, add olive oil. Once heated, add diced onion and sauté for about 4-5 minutes until translucent. Remove onion and set aside.

Add sliced mushrooms to the skillet, cooking for about 5-7 minutes until golden brown. Stir occasionally and then set aside with the onions.

Sauté fresh spinach in the skillet for 2-3 minutes until wilted. Set aside.

In the same skillet, add minced garlic and sauté for about 30 seconds. Deglaze the pan with vegetable broth, then add heavy cream, parmesan cheese, chili pepper flakes, and Italian seasoning. Let bubble for 2-3 minutes.

Add reserved pasta, sautéed onions, mushrooms, and spinach into the skillet, tossing everything together. Gradually stir in reserved pasta water until desired consistency is reached. Cook for 2-3 minutes and serve immediately.