Step 1: Preheat your oven to 350°F (175°C).
Step 2: In a large pot, bring salted water to a boil, add jumbo pasta shells, and cook until al dente. Drain and rinse under cold water.
Step 3: In a mixing bowl, combine ricotta, Italian blend cheese, and egg until well mixed.
Step 4: Stuff each cooked shell with the cheese mixture and place them seam-side up in a greased baking dish.
Step 5: In a saucepan, melt butter, add marinara sauce and heavy cream, stirring until well blended.
Step 6: Pour half of the sauce over the shells, sprinkle with parmesan, then pour remaining sauce over the top.
Step 7: Cover with foil and bake for 25 minutes, then uncover and bake for an additional 10-15 minutes.
Step 8: Garnish with parsley and serve hot.