Preheat oven to 350 degrees F. Grease an 8-inch square baking dish. Heat 2-½ tablespoons of the oil in a large skillet and saute the onion until wilted but not browned, about 4 minutes. Stir in the greens and continue cooking until the greens stop exuding moisture. Remove from heat and cool slightly. Beat the eggs in a large mixing bowl. Beat in the cottage cheese, Parmesan cheese, and salt and pepper to taste. Stir in the greens mixture. Pour into the prepared dish. Drizzle the remaining ½ tablespoon olive oil over the top. Bake for 35 to 40 minutes, or until set.