Melt the butter or margarine in a saucepan over moderate heat. Add the onion and curry powder and cook for 5 minutes, stirring frequently, until the onion is soft but not brown. Add the flour and cook an additional 2 minutes, stirring frequently.
Add the milk, 1/2 cup at a time, stirring until the mixture becomes thick and comes to a boil. Add the sliced or quartered eggs and stir very gently so as to break the egg yolks as little as possible. Remove from the heat and let sit for 2 or 3 minutes until the eggs are warm through. Serve on top of toast.
Servings: