Cook the onion in the butter just until tender. Combine all ingredients until well mixed. Spray 9 x 13 inch pan with nonstick spray, spread mixture evenly in pan.* (Can be covered and refrigerated several hours or overnight at this point.)
Bake uncovered, in 350 degrees F oven until lightly browned on edges and bubbly, about 45 minutes to an hour.
Posted by FootsieBear at Recipe Goldmine 6/12/01 5:32:51 am.
Source: Footsie's own again, adapted from several different recipes