Bring a large pot of salted water to a boil and cook the gnocchi according to package directions until they float. Drain and set aside.

In a large skillet over medium heat, warm the olive oil and butter. Add the onion and cook for 2 to 3 minutes until softened.

Add the sliced mushrooms and cook for 5 to 7 minutes, stirring occasionally, until they release their moisture and begin to brown.

Stir in the garlic and cook for 30 seconds until fragrant.

Pour in the vegetable broth and heavy cream, then add the salt, black pepper, and red pepper flakes if using. Bring to a gentle simmer.

Add the Parmesan cheese and stir until the sauce is smooth and slightly thickened.

Add the spinach and cook for 1 to 2 minutes until wilted.

Gently fold in the cooked gnocchi and toss until fully coated in the creamy sauce. Taste and adjust seasoning if needed.

Serve immediately, garnished with chopped parsley if desired.