Wash eggplants, cut heads and pat dry and slice evenly along their length into 3-4 slices.
Sprinkle some salt over both surfaces of eggplant slices. Let sit for about 10 minutes, then pat dry with paper towels.
Preheat oven to 400 F. Prepare a baking sheet/tray, spray or oil it to prevent sticking.
Arrange eggplants onto baking sheet, bake for 10 minutes or so till pliable. Let cool down at room temperature.
Chop and saute spinach with some olive oil and garlic.
Squeeze spinach to remove excess liquid. Add to a large enough container.
Mix spinach together with all the cheese, leaving 1/2 cup of mozzarella to sprinkle later on.
Have baking dish/pan, spread some marinara sauce on its bottom.
Lay a slice of eggplant on even surface, then spread some of the cheese/spinach mixture all over its surface.
Carefully roll the eggplant slice into roll and arrange onto marinara sauce layer in baking pan.
Repeat for the rest of eggplant rolls.
Now Sprinkle with the remaining mozzarella cheese and cover pan with foil.
Bake for 30 minutes over 350F or until all the cheese is melting.