Melt the butter and pour into the baking dish. For individual servings, you may use 8 three and one half inch ramekins.
In a large mixing bowl, beat the eggs slightly and then stir in the cheeses.
Combine the flour and baking powder and add to the egg mixture, blending thoroughly.
Pour into the baking dish or 8 ramekins and bake for 15 minutes at 400 degrees. Reduce oven temperature to 350 degrees and continue baking for another 20 minutes. Cut into pieces and serve hot. Or serve hot in the individual ramekins
Stir in a small amount of the foods which you have chosen to add such as halved fresh cherry tomatoes, chopped sweet onion, chopped sausage, chopped ham, chopped mushrooms, chopped broccoli, chopped red peppers, or shallots. Let your imagination run wild!