Preheat your oven to 375°F (190°C).
Boil the jumbo pasta shells in a large pot of salted water for approximately 8 minutes until al dente, then drain and set aside to cool.
Heat the extra virgin olive oil in a skillet over medium heat and sauté the minced garlic for 1 minute until fragrant.
Add the ground turkey to the skillet and season with half of the sea salt, black pepper, and dried oregano, cooking until the meat is fully browned and crumbled.
In a medium bowl, combine the part-skim ricotta cheese, liquid egg whites, chopped fresh baby spinach, and the cooked turkey mixture until well incorporated.
Spread 2 tablespoons of the marinara sauce across the bottom of a small oven-safe baking dish.
Generously stuff each cooked pasta shell with the turkey and ricotta mixture and arrange them side-by-side in the baking dish.
Pour the remaining marinara sauce over the shells and sprinkle with the remaining sea salt, black pepper, and dried oregano.
Cover the dish tightly with foil and bake for 20 minutes, then remove the foil and bake for an additional 5 minutes until the sauce is hot and bubbly.