Mississippi Chocolate Gravy

Mississippi Chocolate Gravy
1 cup white sugar
1 tablespoon self-rising flour
1 tablespoon unsweetened cocoa powder
1 1/4 cups water
1 tablespoon butter
In a medium saucepan, combine sugar, flour and cocoa powder. Add water and stir. Bring to a boil over medium heat, stirring occasionally until thick. Remove from heat and add butter. Serve warm.