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.

While the gnocchi cooks, heat the olive oil and butter in a large skillet over medium heat. Add the onion and cook for 2 to 3 minutes, until softened.

Add the mushrooms and cook for 6 to 8 minutes, stirring occasionally, until browned and their liquid has mostly evaporated.

Stir in the garlic, Italian seasoning, red pepper flakes if using, salt, and black pepper. Cook for 30 seconds until fragrant.

Pour in the vegetable broth and simmer for 1 to 2 minutes, scraping up any browned bits from the pan.

Reduce the heat to low and add the heavy cream. Stir in the Parmesan cheese until the sauce is smooth and slightly thickened.

Add the spinach and cook, stirring, until wilted, about 1 to 2 minutes.

Add the cooked gnocchi to the skillet and gently toss to coat in the creamy sauce. Cook for 1 to 2 minutes more until heated through.

Taste and adjust seasoning if needed. Serve warm topped with extra Parmesan and chopped parsley.