Bring a large pot of salted water to a rolling boil. Add 24-30 jumbo pasta shells and cook for 10-12 minutes until al dente, firm to bite but not crunchy. Drain and rinse with cold water to stop cooking, then lay shells flat on a baking sheet to prevent sticking.
24 shells jumbo pasta shells
Heat 1 tablespoon olive oil in a skillet over medium heat. Add minced garlic and cook 30 seconds until fragrant. Add fresh spinach in batches, cooking 3-4 minutes until wilted. Transfer spinach to a fine-mesh sieve or bowl lined with paper towels and press hard to remove all moisture, then chop roughly.
10 oz fresh spinach, 3 cloves garlic, 1 tbsp olive oil
In a large bowl, combine ricotta, 1 cup mozzarella, grated parmesan, egg, Italian seasoning, chopped sautéed spinach, salt, and pepper. Stir until evenly mixed and no egg streaks remain.
2 cups ricotta cheese, 1.5 cups mozzarella cheese, 0.5 cup parmesan cheese, 1 large egg, 10 oz fresh spinach, 2 tsp Italian seasoning, 0.5 tsp salt, 0.25 tsp black pepper
Preheat oven to 350°F. Spread 1 cup marinara sauce evenly in the bottom of a 9x13-inch baking dish. Using a spoon or piping bag, fill each cooked shell with about 2 tablespoons of cheese mixture. Arrange stuffed shells opening-side up in the prepared dish. Pour remaining 2 cups marinara sauce over shells and sprinkle remaining ½ cup shredded mozzarella on top.
1.5 cups mozzarella cheese, 3 cups marinara sauce
Cover the baking dish tightly with aluminum foil and bake for 25 minutes. Remove foil and bake for an additional 10-15 minutes until cheese is melted, lightly golden, and sauce is bubbly around edges. Remove from oven and let rest uncovered for 10 minutes before serving to let filling set.
