In a skillet saute onions in butter till tender and translucent.
Remove from heat and stir in Sour Cream.
Spoon half of mixture into a greased 1 qt. baking dish.
Sprinkle with Parmesan cheese.
Top with remaining onion mixture and then crushed crackers.
Bake uncovered at 350 degrees for 20-25 minutes.
Makes 4-6 servings