Saute onion in butter and olive oil for 3 minutes over medium heat. Add spinach (thawed and drained) and saute for another 10 minutes. Do not brown.
In large bowl, lightly beat eggs with fork. Add cottage cheese, feta cheese, dill and spinach onion mixture. Pour into pie crust and top with grated Parmesan cheese. Bake at 350 degrees for 60 minutes or until slightly brown on top. Cool before cutting. Best eaten warm, not hot.