Preheat the oven to 375°F. Cook jumbo pasta shells according to package instructions. Drain and rinse with cold water. In a large bowl, mix together blanched asparagus spears, ricotta cheese, grated Parmesan cheese, chopped fresh parsley, salt, and pepper. Stuff the shells with the mixture and place them in a baking dish. Pour tomato sauce over the shells. Bake for 20-25 minutes, until the sauce is bubbly and the shells are heated through. Serve hot with garlic bread.