Bring a large skillet with one half inch of water to a boil.
Trim the ends from the eggplant and using a vegetable peeler, peel the eggplant. You can also use a sharp knife. Then slice the eggplant into 1/2" slices
Place the slices in the boiling water until JUST tender (do not overcook as these will continue in the oven). About 5 minutes or so.
Drain excess water on paper towels.
TO PREPARE THE MEAT SAUCE:
Add a small amount of oil to a skillet with onions and ground beef.
Add garlic, if desired and the tomato sauce. Season with salt and pepper, cooking down until a bit thickened. Set aside.
TO PREPARE THE CHEESY WHITE SAUCE:
Whisk all ingredients together in a small saucepan over medium high heat until thickened.
TO ASSEMBLE:
Preheat oven to 350 degrees.
Spray a baking pan with cooking spray, then add one layer of eggplant slices. Top with with meat sauce and repeat with another layer of eggplant then meat sauce.
Drizzle with the white sauce and top with parmesan.
Bake until golden and bubbly, allowing to cool slightly before serving.