Cut ends off of eggplant. Carefully slice lengthwise, about ¼ inch thick. (Don't worry if some of your slices are too thin or uneven. You can layer pieces together that are uneven).
Liberally salt both sides of the eggplant and let sweat for 15 minutes. After 15 minutes, there should be moisture on your slices. Pat slices dry with a paper towel wiping away salt.
Use enough olive oil to grease two sheet pans. Lay eggplant slices out so they aren't overlapping. Bake for 10 minutes. Remove and allow to cool for 10 minutes. (This will make them easier to roll).
Assemble
In a 9 x 9 glass baking dish, pour ½ - 1 cup of the tomato sauce evenly spreading it out. Lay a slice of the eggplant in the sauce. Use a spoon to dollop (about 1 - 2 Tbsp) of the ricotta onto the slice, placing it closer to one end. Roll up the slice and lay (seam side down) against the edge of the dish.
Repeat until all eggplant has been used or you run out of ricotta lining them up together tightly. (If some eggplant slices are too thin or uneven, use two at a time).
Pour remaining sauce on top and spread evenly. Top with cheese, if desired. Cover with foil and bake for 30 minutes. Remove foil and bake for another 10. Allow to cool and enjoy.