In a medium pot over medium heat, warm 2 tablespoons of olive oil. Add minced garlic and finely chopped shallots, sautéing until the onions turn translucent, about 3-4 minutes. Stir in 2 tablespoons of tomato paste and cook for another minute. Pour in 1 cup of white wine, allowing it to simmer until mostly evaporated, about 2 minutes. Then, add 28 ounces of tomato passata, 1 tablespoon of sugar, salt, and pepper. Keep it on low heat, uncovered, for 20 minutes until slightly thickened.

While the sauce simmers, squeeze excess water from 10 ounces of thawed spinach. In a large mixing bowl, blend 15 ounces of ricotta cheese, ½ cup of grated Parmesan, 1 cup of shredded cheese, 1 minced garlic clove, 1 egg, and a pinch of nutmeg, salt, and pepper. Mix until creamy and well-combined.

Preheat your oven to 400°F (200°C). Start filling each jumbo pasta shell with about 2 tablespoons of the ricotta-spinach mixture. In a 9 x 13 inch baking dish, pour a layer of the hot tomato sauce to cover the bottom. Arrange the filled shells atop the sauce, ensuring they are mostly submerged.

Cover the baking dish tightly with aluminum foil and bake for 70 minutes until the shells are tender and sauce is bubbling. Remove the foil, sprinkle the remaining shredded mozzarella and Parmesan over the top, and bake uncovered for an additional 15 minutes.

Let your Spinach Ricotta Stuffed Shells cool for a few minutes. Garnish with fresh basil leaves and an optional sprinkle of extra Parmesan.