Sauté aromatics:
Heat the olive oil in a large skillet over medium-high heat. Add the chopped onion and cook for about 5 minutes, stirring occasionally, until softened and lightly golden.

Add mushrooms and garlic:
Stir in the sliced mushrooms, minced garlic, and Italian seasoning. Cook for another 5 minutes, allowing the mushrooms to release their moisture and begin browning.

Deglaze and add flavor:
Add the Dijon mustard and pour in the white wine. Stir and let it simmer for about 1 minute to reduce slightly.

Cook the gnocchi in the sauce:
Pour in the heavy cream and stir in the uncooked gnocchi. Bring the mixture to a gentle simmer, then reduce the heat to medium-low. Cover and cook for about 3 minutes.

Add spinach:
Remove the lid, stir in the spinach, then cover again and cook for another 3 minutes, until the spinach has wilted and the gnocchi are soft.

Finish with parmesan:
Stir in the parmesan cheese until melted and the sauce becomes creamy. Season with salt and pepper to taste. If the sauce is too thick, add a splash of wine or cream to thin it.

Serve and garnish:
Sprinkle with fresh parsley and extra parmesan cheese before serving. Enjoy hot and creamy right from the skillet!