When it comes to baking cakes, the spongy, flavoured inside is only part of what it takes to impress your guests and make their mouths water. In addition to the aesthetic beauty it can provide, sweet, fluffy icing enhances the flavour and texture of your cakes. There are almost as many techniques for icing as there are for baking cakes, but one of the most common is making flat, wide icing "ribbons," which dress up the base layer of icing you use to frost the surface of the cake.
Prepare icing in advance, or buy icing from the grocery store. If you prepare or buy white icing, add any necessary food colouring to it, prior to decorating your cake. You won't be able to change its colour once you've applied it.
Cut a hole in the corner of your plastic bag. If you have a ribbon icing tip, cut the hole precisely on the corner and insert the tip down into the bag and through the hole. If you don't have a tip, cut a narrow, long slit on the flat, plastic face of the bag just above the corner. This shape will make the icing flow out of the bag in a wide, flat ribbon.
Pour icing into the plastic bag, using a plastic spatula, if necessary, to aid in scraping excess icing from the sides of its original container. Once it's all inside, squeeze it down so that it collects in one -- but not both -- of the bag's bottom corners.
Hold the icing bag over the cake with both hands at the top of the bag, just where the icing level stops. Squeeze gently so that the icing comes out slowly, making whichever shapes -- roses, for example -- or borders you'd like. If you happen to make a mistake, use a spatula or butter knife to slough the icing off your cake and start over. Going slowly will reduce your tendency to make such errors.
If you don't like the ribbon shape, use a special tip to change it. Cutting a hole exactly at the bottom corner of the bag without using a tip will result in cylindrical tubes of icing rather than flat, wide ribbons. Decorative tips allow you to create scalloped icing shapes and edges of varying thickness and roundness.