Doughnuts are often filled with either jam or jelly and dusted with icing sugar — Jelly Doughnuts — or filled with custard and topped with a chocolate glaze — Boston Creams.
Place the filling (about 1½tablespoons per doughnut) into a piping (icing) bag fitted with a plain narrow nozzle. Poke a hole in your doughnut using a chopstick or something similar. Insert the nozzle into the hole and gently squeeze the filling into t