Spinach and Mushroom Stuffed Shells

Name: Spinach and Mushroom Stuffed Shells
Ingredients: Olive oil, for greasing; Kosher salt and freshly ground black pepper; 8 ounces jumbo pasta shells (20 to 24); 10 ounces cremini mushrooms, stems trimmed, coarsely chopped; 1 shallot, coarsely chopped; 3 tablespoons unsalted butter; 8 ounces baby spinach; 2 tablespoons chopped fresh parsley; One 15-ounce tub whole milk ricotta; 1/2 cup pine nuts, toasted; 3 to 4 large leaves fresh basil, chiffonade, plus whole leaves for garnish; 1 1/2 cups grated mozzarella; 1/2 cup grated Parmesan, plus more for serving; 2 1/2 cups Vodka Sauce, recipe follows, or your favorite jarred sauce, warmed; 1 tablespoon unsalted butter; 1 small yellow onion, finely chopped; 1 clove garlic, minced; Pinch red pepper flakes; One 14-ounce can diced tomatoes; 1/2 cup heavy cream; 1/4 cup vodka; 2 tablespoons tomato paste; Pasta cooking water, for adjusting sauce consistency