Heat the oven to 400 F. Lightly coat a muffin pan or baking sheet with cooking spray; set aside. In a medium saute pan, add oil and saute the onions until soft and tender, about 5 minutes. Set aside to cool. In a medium bowl, combine the remaining ingredients with the cooked onions. Mix well. Mixture should be fairly thick. Place 1/4 cup of mixture into each muffin slot or spread mixture on the prepared baking sheet. Bake for 18 to 22 minutes or until a toothpick comes out clean. Serve warm.