Step 1: Cook the Pasta Shells

1. Bring a large pot of salted water to a boil.
2. Cook the jumbo pasta shells until al dente, according to package instructions.
3. Drain the shells, toss with olive oil to prevent sticking, and set aside to cool.

Step 2: Prepare the Meat Sauce

1. Heat 1 teaspoon olive oil in a large skillet over medium heat.
2. Sauté the onions and garlic until fragrant and translucent, about 2–3 minutes.
3. Add the ground turkey and cook until browned, breaking it into small pieces.
4. Stir in crushed tomatoes, fresh basil, and salt and pepper to taste.
5. Cover and let simmer on low heat for 15 minutes.

Step 3: Make the Cheese Filling

1. In a large mixing bowl, combine ricotta cheese, shredded mozzarella, grated Parmesan, egg, and thawed spinach.
2. Mix until well combined.

Step 4: Stuff the Pasta Shells

1. Spoon about 2 heaping tablespoons of the cheese filling into each cooked shell.
2. Spread a layer of meat sauce on the bottom of a large baking dish.
3. Arrange the stuffed shells seam-side up over the sauce.

Step 5: Bake the Dish

1. Preheat the oven to 375°F.
2. Spoon half of the remaining meat sauce over the shells.
3. Cover the baking dish with foil and bake for 40 minutes.
4. Remove the foil and bake for an additional 5 minutes to lightly crisp the top.

Step 6: Serve and Enjoy

1. Garnish the baked shells with fresh basil and grated Parmesan cheese.
2. Serve warm with additional meat sauce, crusty bread, or a fresh green salad.