Spinach, Mushroom, & Ricotta Stuffed Shells

Source:  http://www.handletheheat.com/2011/03/spinach-mushroom-ricotta-stuffed-shells.html
Adapted from Real Simple
Serves 4-6

• 20 jumbo pasta shells (about half a 12-ounce box)
• 1 24-ounce jar marinara sauce (or 3 cups homemade sauce)
• 1 15-ounce container part-skim ricotta
• 2 cups baby spinach, chopped
• 2 tablespoons chopped fresh basil
• 8 oz chopped mushrooms
• 1/2 cup grated Parmesan (2 ounces)
• kosher salt and freshly ground black pepper
• 1/2 cup grated mozzarella (4 ounces)

1. Set an oven rack to the highest position and heat oven to 400° F. Cook the pasta according to the package directions. Drain and run under cold water to cool.
2. Spread the marinara sauce in the bottom of a large broilerproof baking dish.
3. In a bowl, combine the ricotta, spinach, basil, mushrooms, Parmesan, ½ teaspoon salt, and ¼ teaspoon pepper. Spoon the mixture into the shells and place them on top of the sauce. Alternatively, transfer mixture into a large ziploc bag, snip one corner, and pipe filling into shells.
4. Sprinkle the shells with the mozzarella and bake until heated through, 10 to 12 minutes.
5. Increase heat to broil. Broil the shells until cheese begins to brown, 2 to 5 minutes. Serve with the salad.