Add the olive oil to a skillet on medium-high heat to warm. Add the onion and sauté for 5 minutes, stirring occasionally.
Add the mushrooms, garlic, and Italian seasoning. Cook for another 5 minutes stirring occasionally,
Add the Dijon mustard and white wine, mix well. Let it bubble for a minute or so.
Add the cream and gnocchi and mix well. Wait until it starts to bubble again, then cover and reduce the heat to medium-low. Cook for 3 minutes.
Add the spinach, mix well, cover and cook for 3 minutes.
Stir in the parmesan and season with salt & pepper. Give it a taste; gnocchi should be soft. If not, continue to cook for another few minutes. Serve immediately with more parmesan cheese grated over top if desired.
Notes
I made this in my dutch oven. Easily one of my favorite kitchen tools. It heats evenly and holds heat well and makes for easy cleanup.