1 cup Grated Parmesan Cheese, Plus More For Sprinkling
1 whole Large Egg
12 ounces, weight Jumbo Pasta Shells (25 To 30 Shells) Cooked Until Slightly Firmer Than Al Dente
YIELD 12 servings
Heat the olive oil in a large skillet over medium heat. Add the onion and garlic, and saute until the onion starts to soften, about 4 minutes. Add the spinach and cook, stirring continuously, until it's slightly wilted, about 2 minutes. Remove the spinach from the pan and let it cool slightly, then place it inside a few paper towels and squeeze out as much liquid as you can. Give it a rough chop and set it aside.
Turn the heat to medium-low, then, in the same skillet, melt the butter and sprinkle the flour over the top. Whisk it together to make a roux, then cook it for a minute or two. Slowly add the milk, whisking out lumps as you go, and cook it until the white sauce is thickened, 4 to 5 minutes. Turn off the heat and stir in half the basil, half the parsley, and salt and pepper to taste. Add another 1/4 cup milk if the white sauce is too thick. Taste and adjust the seasonings.
In a separate bowl, mix together the ricotta, Parmesan, egg, the rest of the basil, the rest of the parsley, and salt and pepper to taste until combined. Stir in the chopped spinach mixture.
To assemble the shells, use a spoon to fill the pasta shells with the cheese mixture. Place the shells seam side down in a 9 x 13 casserole dish or disposable foil baking pan. Pour the marinara evenly over the shells, then ladle the white sauce over the marinara in a zig-zag/line design. Finally, sprinkle with more Parmesan.
Bake it in a preheated 375 degrees for 25 to 30 minutes, until hot and bubbly.
***To freeze, cover the unbaked shells tightly with heavy foil and freeze for up to 6 months. To bake the frozen casserole, place it in a 375 degree oven for 1 1/2 hours, then uncover and continue baking for 10 to 30 minutes, depending on how frozen it was. OR ***Thaw the pan in the fridge for 24 to 48 hours, then bake as directed.