Preheat oven to 350°F.
Line 2 baking sheets with parchment paper or aluminum foil. (If using foil, spray or brush the foil with olive oil.)
Add half the Parmesan cheese, all of the breadcrumbs, and the remaining 1 tsp salt to a bowl, and stir to combine. The beaten egg should be in a different bowl, right next to the breadcrumb mixture.
One at a time, dip eggplant slices in egg and then in breadcrumbs, coating both sides.
Note: If you have trouble getting the breadcrumbs to stick, simply dip the eggplant in egg and then sprinkle the crumbs on top. Skip flipping the eggplant. (This may happen if your eggplant slices are still moist, especially with homemade breadcrumbs or larger Panko breadcrumbs.) Set eggplant in single layer on baking sheets, and bake 5-7 minutes, flip, and bake 5-7 more minutes (10-14 minutes total).
Note: The cook time will depend on how thinly you've sliced the eggplant. Watch the eggplant the last few minutes in the oven, and remove when they appear golden and crisp. While eggplant is baking, pour half the tomato sauce in a 8"x8" pan (or small casserole dish). Sprinkle half the green onion over the mixture.
When eggplant is finished baking, layer half of the eggplant on top of the sauce.
Next, spread the ricotta over the eggplant into one layer. Top the ricotta with the remaining eggplant.
Add remaining tomato sauce, and top with remaining Parmesan.
Bake uncovered 20-25 minutes, until the cheese have melted and the eggplant is totally cooked through.
Before serving, top with the remaining green onion.
Serve hot along with pasta, crusty bread, or a green salad.
Leftovers:Store leftovers in the fridge, and use within 1-2 days.