Ever wonder how some people get a nice, smooth edge on their buttercream cakes? I’ve tried several techniques but I learned that starting with even cake surfaces is best. Follow these five steps for a smooth buttercream cake.
How to get a smooth buttercream finish on a cake
1. Trim away domes, lumps and bumps. Use a serrated knife and a gentle sawing motion to trim. Wipe away all crumbs.
2. Apply a thin layer of buttercream to your cake to seal in any crumbs. This is also known as crumb coating. Allow about 10 minutes to dry at room temperature.
3. Apply a thick layer of buttercream. How thick? About a 1/4 – 1/2″. Or this thick:
Swipe the edge of your spatula on a bowl’s lip to remove excess icing and smooth the cake’s surface as best as you can.
4. Now, it’s all about allowing your buttercream to crust over. Allow about 15 minutes to dry at room temperature. You might need more time to allow the icing to crust if your buttercream is thin or you’re working in humid conditions. Gently touch an inconspicuous area of the cake. If your finger comes away with no icing on it, you’re ready for the next step.
5. Lay a large strip of parchment paper on the cake to work as a barrier between the icing and your fondant smoothers. Use fondant smoothers to rub and smooth your icing into shape.
My cake could’ve used another layer of buttercream to better hide some crumbs I pulled up while crumb coating and more buttercream would’ve given me more room to smooth out lumps and bumps. You need enough icing on your cake so that you can push icing around to fill gaps without revealing the cake’s surface. Match your crumb coat icing colour to the finished icing colour to avoid patches of colour showing through. My cake had a few white patches of crumb coat peeking out in some places.
Allowing buttercream to crust is key to achieving a smooth finish.
You’ll have to use your best judgment to determine how much pressure to apply. Press firmly enough to smooth the icing but not so firm as to leave dents or expose the cake’s surface.
And there you have it! Smooth buttercream.
Want to see how I decorated this cake? Read How to make a brush embroidery cake.