In a large bowl mix together the potato slices with 6 tablespoons melted butter, 1/2 cup grated Parmesan cheese (can use more than 1/2 cup Parmesan cheese if desired) seasoned salt, or white salt and black pepper to taste; toss well using clean hands to combine.
Arrange the potato slices in several layers sprinkling the green onion over the layers.
Drizzle more butter over the top layer, then sprinkle with about 1/4 cup (or to taste) grated Parmesan cheese.
Bake uncovered for about 1 hour, or until the potatoes are tender.
Loosen potatoes from the sides and bottom of the pie plate and invert immediately onto a serving plate.