Preheat oven to 350.
Spray a 1 quart baking dish with cooking spray.
In a medium size saucepan, stir together the broth, milk, sugar, salt and cornmeal, then bring to a boil over moderate heat. Add 2 tsp of the butter and cook the mixture over low heat, whisking occasionally, for 5 minutes.
Transfer to a large bowl and stir in the cayenne pepper and nutmeg.
In a nonstick skillet, cook the sweet red pepper and onion in the remaining 2 tsp of butter over moderate heat for 3 minutes or until softened, stirring occasionally; add the corn and cook the mixture, stirring, 1 minute more. Stir into the cornmeal mixture. In a small bowl, whisk the egg yolks with the baking powder, then stir them into the cornmeal mixture. Beat the egg whites until stiff but not dry.
Stir 1/4 of the whites into cornmeal mixture, then gently fold in the rest. Pour the mixture into the prepared baking dish and bake for 40 minutes or until puffed, then broil 4" from the heat for 1 to 2 minutes or until golden brown.
Serve at once directly from the dish.