Over medium heat, in a medium saucepan with extra-virgin olive oil, sautè the garlic for one minute. When it turns golden, sautè the spinach for about 5 minutes. Season with salt and pepper. Set aside and let it cool.
When the spinach has cooled down, add the Parmesan and mozzarella.
Prepare two plates with extra-virgin olive oil for coating the rolls and another one with the breadcrumbs.
Using a meat tenderizer, pound the chicken filets until they’re thin enough to easily roll. Cut each in half lengthwise.
Lay a chicken filet on a plate, then add a layer of spinach mixture on top. Tightly roll the chicken, starting at one short end. Lightly coat the outside of the rolls with extra-virgin olive oil.
Coat the chicken with the breadcrumbs, pressing crumbs onto the rolls as needed. Place the rolls on a baking pan lined with parchment paper.
Bake for 30 minutes or until the chicken rollatini with spinach are cooked through and golden.