Spinach & Ricotta-stuffed shells from 12tomatoes.com

24 jumbo pasta shells or lShellsumaconi
1 (15 oz.) container ricotta
4 cups fresh spinach
2 cups mozzarella cheese, grated, divided
1 cup heavy cream
1/2 cup parmesan cheese, grated
3 tablespoons unsalted butter
3 tablespoons all-purpose flour
1 tablespoon lemon juice
1/4 teaspoon ground nutmeg
kosher salt and freshly ground pepper, to taste

Preheat oven to 400º F.
Bring a large pot of salted water to boil and cook pasta according to packaging directions, or until just al dente. Reserve pasta water, drain and set aside.
Return pasta water to heat and blanch spinach until just wilted. 30-60 seconds, or until bright green.
Remove spinach from boiling water and immediately place in an ice bath to prevent further cooking.
Drain spinach, then place in a large bowl and mix together with ricotta.
Season generously with salt and pepper, then transfer mixture to food processor or blender and pulse until spinach is chopped into small pieces.
Fold 1 cup mozzarella cheese into ricotta mixture, then use a spoon to stuff your shells with cheesy spinach filling. Place stuffed shells in a 9×13-inch baking dish.
Melt butter in a large saucepan over medium-high heat and whisk in flour to create a roux.
Cook for 1 minute, stirring constantly, or until mixture is smooth and paste-like.
While continuing to whisk, slowly mix in heavy cream. Bring to a boil and cook for 5 minutes, or until thickened.
Add remaining mozzarella and cook until completely incorporated. Season with lemon juice, nutmeg and salt.
Pour sauce over stuffed shells, then sprinkle parmesan over the top.
Cover with aluminum foil and place in oven. Bake for 20 minutes, then uncover and bake for another 15.
Remove from oven and let cool 5 minutes, then serve hot.