Cabbage roses are very full, flouncy blooms and make great decorations for cakes. While cabbage roses can be made from both fondant and gum paste, gum paste tends to yield the most realistic-looking flower, as it can be rolled thinner than fondant. Making cabbage roses from gum paste is quite time consuming; however, you can make them well ahead of time and keep them in an airtight container until needed.
Roll out gum paste in your chosen colour to 3 mm (1/8 inch) thick. Use a 2.5 cm (1 inch) long teardrop cutter to cut out shapes for the rose petals, around 18 to 20 for each rose.
Cover the teardrops in cling film so they don't dry out. Roll a small piece of gum paste into a ball, around 6 mm to 1.2 cm (1/4 inch to 1/2 inch) wide. Stick a piece of wire or a toothpick into the ball to make assembling the rose easier.
Remove 1 teardrop from under the cling film. Use a ball roller or a sterilised marble to roll out the rounded end of the teardrop so that it is very thin and slightly uneven, like the edge of a real rose petal. If you don't have a ball roller or a marble, you can squish the edges of the teardrop between your fingers for a similar effect.
Wrap the teardrop around the ball on the wire or toothpick, while holding the wire or toothpick in your hand. The pointed end of the teardrop should be toward the wire. Wrap this first petal quite tightly around the ball, pulling back the thinned edges slightly.
Flatten the edges of another teardrop and wrap it around the ball like you did the first one, opposite the first petal on the ball. Smooth both of the petal points underneath the ball.
Repeat with the remaining petals, staggering their position around the ball and pulling out their edges more sharply as you reach the outer petals of the rose. Make the edges of the middle and outer petals more ruffled, as cabbage roses are flouncier than normal roses. If need be, use a very small amount of water painted onto the petal with a paintbrush to act as a glue if the gum paste is a little dry.
Remove the wire or toothpick from the underside of the cabbage rose and trim any excess gum paste from the bottom. You can also leave the wire or toothpick in the rose if you want to use it to help attach the rose to a cake.
Gum paste dries very quickly, especially when rolled thinly. When not using, keep under cling film. If you have to stop making your cabbage rose part way through, place it under cling film until you can resume.