Preheat your oven to 375°F (190°C).
Cook the jumbo pasta shells in a large pot of boiling salted water according to package directions until al dente, then drain and set aside to cool.
In a medium skillet over medium heat, add the olive oil and ground turkey, sautéing and breaking the meat into small crumbles until browned and cooked through.
Add the minced garlic to the skillet and cook for 1 minute until fragrant, then pour in the marinara sauce and let it simmer on low.
In a separate pan, wilt the fresh baby spinach with a tablespoon of water over medium heat, then drain and squeeze out all excess moisture before finely chopping.
In a mixing bowl, stir together the part-skim ricotta, chopped spinach, egg white, sea salt, and black pepper until well combined.
Spread a thin layer of the turkey marinara sauce across the bottom of a small oven-safe baking dish.
Carefully stuff each cooked pasta shell with a generous portion of the spinach and ricotta mixture and arrange them in the baking dish.
Spoon the remaining turkey marinara sauce over the stuffed shells and sprinkle evenly with the parmesan cheese.
Bake for 20 minutes until the sauce is bubbly and the cheese has formed a light golden crust.