Position a rack in the center of the oven and heat to 375°F.
Heat the oil in a large skillet on medium heat until it shimmers. Add the garlic and cook until just fragrant, 30 seconds. Add the spinach a handful at a time and cook until it wilts. To the wilted spinach add the crushed red pepper flakes and 1 tsp. salt, and stir until combined. Transfer the spinach to a medium mesh strainer and press out as much liquid as possible, then coarsely chop.
Put the Ricotta con Latte in a large bowl, add the spinach, grated parmesan, pine nuts, egg, zest, ½ tsp. salt, ¼ tsp. pepper, and fold together with a silicone spatula until well combined. Adjust the seasoning to taste with crushed red pepper flakes, salt, and pepper.
Lightly oil the bottom and sides of a 9 ×13 inch straight-sided ceramic or glass baking dish. Stir the granulated garlic into the sauce. Spread 1 cup of the sauce evenly over the bottom of the dish. Fill each shell with about 2 Tbsp. of the ricotta mixture (you may not use all of the shells), and transfer to the baking dish, arranging as many shells, open side up, as can comfortably fit. Dollop 2 cups of the sauce around the shells and top evenly with the Fresh Mozzarella.
Lightly oil one side of a piece of foil large enough to cover the dish. Cover the shells with the oiled side of the foil, and bake until the cheese melts and the sauce is bubbling, about 35 minutes. Remove the foil, turn the oven to broil, and broil until the cheese begins to brown, 3 to 4 minutes. Cool for 10 minutes, garnish with the herbs, and serve with the remaining 1 cup sauce and grated Parmesan cheese at the table.