Heat oven to 400°F. Grease or spray bottom of 8-inch cast-iron skillet. Heat skillet in oven about 10 minutes or until hot. (Or an 8-inch square pan can be used; no preheating required in oven.)
In medium bowl, mix all ingredients. Pour into skillet.
Bake about 15 minutes or until toothpick inserted in center comes out clean. Loosen sides with knife, and carefully remove from skillet to cooling rack to cool.