1-First Step: Preheat the oven to 375°F (190°C) and bring a large pot of salted water to boil for cooking the jumbo shells.

2-Second Step: Cook the pasta shells according to package instructions until al dente. Drain and lay them flat on a baking sheet to prevent sticking.

3-Third Step: In a skillet, heat olive oil over medium heat. Sauté minced garlic until fragrant, then add mixed seafood. Cook until just opaque, about 3-4 minutes. Remove from heat.

4-Fourth Step: In a bowl, combine ricotta, half of the mozzarella, parmesan cheese, sautéed seafood, and chopped parsley. Mix well and season with salt and pepper as needed.

5-Fifth Step: Spread a layer of marinara sauce evenly on the bottom of a baking dish.

6-Sixth Step: Stuff each cooked shell with the seafood and cheese mixture and place them seam side up in the baking dish.

7-Seventh Step: Cover the shells with the remaining marinara sauce, then sprinkle with the remaining mozzarella cheese.

8-Eighth Step: Bake uncovered for 25-30 minutes until the cheese is melted and bubbly and the sauce is heated through.

9-Final Step: Let the stuffed shells cool for 5 minutes before serving. Garnish with extra fresh parsley. For dietary adjustments, substitute plant-based cheeses and seafood alternatives as needed during the filling preparation stages.