In a large skillet over medium heat, add olive oil. Once hot, add leek and onion and cook for about 3 minutes. Add a pinch of salt and remember to continue to add it in layers for flavor! Add garlic and cook for another 2-3 minutes until fragrant.
Add cherry tomatoes; cook until they begin to blister, about 5 minutes, and then begin to smash them down gently with the back of your spoon. Let the juices cook about 1-2 minutes.
Deglaze the pan with white wine or vegetable stock. Bring it back to a simmer and let it cook down for 1-2 minutes. Stir in the butter to melt.
Add in the gnocchi, stir to coat in the sauce, and make sure they are in a single layer to cook evenly. Bring to a simmer and cover the pan (use foil or a baking sheet if you don't have a lid) and cook about 2 minutes longer than the package suggests. Since they won't be submerged in boiling water, they generally take a little longer to cook. I usually cook mine for about 4-5 minutes total. Stir once or twice, and be sure to taste test, they will be soft and pillowy when done!
A minute before the gnocchi is done, stir in parmesan cheese and half-and-half. Then, stir in the spinach until wilted. Add additional vegetable stock if needed for desired consistency.
Serve immediately with additional parmesan and/or a garnish of fresh basil or chopped parsley as desired.
