The perfect petals on professionally decorated cakes make roses appear impossibly difficult, but they're actually quite easy to make once you master the basic, repetitive motions. Roses are even easier to pipe onto cupcakes because you can cover the entire top without needing to transfer the finished roses, as you would for a cake. A large, opened rose is the most time-consuming and difficult to master, so try rosette swirls if you're short on time.
The Right Tools for the Job
Frosting roses requires a large petal decorating tip, which has a slanted tip that is wider at the base than at the top. Insert the petal tip inside a decorating bag. Roses hold their shape best when made with a crusting buttercream frosting that substitutes solid vegetable shortening for all or part of the butter in a traditional buttercream recipe. Food coloring gels and powders work well to color the frosting without thinning it. You can mix different colors in the bag to create swirls or wipe some food coloring on the inside of the bag to streak the frosting.
You Nailed It!
A flower nail is used to pipe frosting roses for cakes because it has a flat platform mounted on a stick that you can spin easily; the finished roses are transferred to the cake. This isn't necessary for cupcakes because you can hold the cupcake by the base in one hand to turn it as needed while holding and squeezing the frosting with the other hand. The petals require a support system in the center to keep them from caving in, so squeeze out a cone of frosting in the center. Hold the tip with the wide opening touching the center of the cupcake; the opening should be perpendicular with the top of the cupcake while the bag is horizontal. Squeeze a ribbon of frosting from the tip while spinning the cupcake a few times to create a cone for the center of the flower.
Layers of Petals
After establishing a strong center of icing, you can apply pipe on the petals. Hold the tip next to the central frosting cone with the tip perpendicular to the cupcake top. Squeeze the bag with medium pressure to push frosting through the tip. As the frosting flows out, move the tip up and down in a slight hump shape to create the curves of the petals. Reposition beside the first petal and make a second petal; repeat this all the way around the center cone. Position the frosting tip at the center of the first petal and make a new petal that ends at the center of the second petal. Continue until you complete the second ring of petals, staggering each petal on the joints of the petals in the previous row. Build up as many layers as it takes until you reach the outer edge of the cupcake.
Take a Shortcut
Large, piped roses certainly look impressive, but it can take several minutes or more just to complete one rose, which isn't very practical for decorating several dozen cupcakes. Instead, you can insert a large star decorating tip in the decorating bag to create a rosette swirl with ridges in the frosting that looks like an unopened rose. Hold the frosting bag perpendicular with the cupcake top and squeeze out a star in the center. While applying constant, medium pressure to the decorating bag, bring the tip to just outside the star shape and swirl the stream of frosting in a spiral pattern two or three times until you reach the outer edge. You can frost a whole cupcake in 10 seconds or less.