Bring a large pot of salted water to a boil over medium high heat. Keep it at a rolling boil until you’re ready to cook the gnocchi.
Heat a large high sided skillet over medium heat. Add the olive oil and onion. Season with kosher salt and cook for 4-5 minutes or until the onion is soft and just beginning to brown.
1 tablespoon olive oil, ½ cup diced onion, ⅛ teaspoon kosher salt
Add the garlic and thyme and cook for another minute.
2 cloves garlic, ½ teaspoon dried thyme
Add the butter and stir until it has completely melted. Sprinkle over the flour and stir until the mixture thickens and begins to bubble. Cook for an additional minute.
2 tablespoons unsalted butter, 2 tablespoons all-purpose flour
Slowly add the milk, stirring constantly. If there are any large lumps of roux, whisk them until smooth.
1 cup whole milk
Bring the sauce to a bubble and cook just until it has thickened enough to coat the back of a spoon– about 5 minutes. Once the sauce has thickened, remove it from the heat and add the ground nutmeg. Season with salt and pepper to taste.
¼ teaspoon ground nutmeg
Add the gnocchi to the boiling water and cook for the time designated on the package– usually about 3 minutes.
16 ounces dried gnocchi
While the gnocchi cook, add the parmesan, spinach, and lemon juice to the cream sauce and stir to combine. The spinach may not fully wilt yet– that’s okay!
½ cup grated Parmesan cheese, 4 ounces fresh spinach, 1 lemon
Once the gnocchi rise to the top of the pot, they are ready! Scoop out the gnocchi (a spider strainer works best here) and add them to the spinach cream sauce. Toss to combine.