01 -  Boil jumbo pasta shells in salted water according to package instructions until al dente. Drain and set aside to cool slightly. 
 02 -  In a medium bowl, combine ricotta cheese, chopped spinach, and minced garlic. Mix until evenly incorporated. 
 03 -  Fill each cooked shell with the ricotta and spinach mixture using a spoon. 
 04 -  Spread a thin layer of Alfredo sauce on the bottom of a baking dish. Arrange stuffed shells in a single layer over the sauce. 
 05 -  Spoon the remaining Alfredo sauce evenly over the stuffed shells. Sprinkle shredded mozzarella cheese on top. 
 06 -  Bake in a preheated oven at 350°F (180°C) for 25 minutes, until hot and bubbly with lightly golden cheese.