Easy Sharp Edges on a Cake

Sharp edges on a cake make any cake look instantly more professional, with clean lines from the sides up onto the top. In this tutorial I’ll walk you through exactly how to get sharp edges on a cake using simple techniques and tools, with all of my tips and tricks to make it easier.

How to prepare a cake for sharp edges on a cake

Start with a cold cake. Wrap your cake and leave it in the fridge for an hour or overnight or place it unwrapped in the freezer for about 15 minutes. This makes the cake much firmer and less crumbly, which makes the process easier and neater. Assemble your cake by attaching the first layer to a cake board with a small amount of buttercream. This acts as glue so it doesn’t move around. Spread on a layer of filling next. I’m using my 4 Minute Buttercream with Nutella mixed in and it's delicious! Then place your next layer on top, making sure it’s centered so the cake is straight, not leaning.

Repeat with more filling and cake layers. You’ll notice that assembling a cold cake is much easier than working with a room temperature cake, which tends to crumble and slide around as you spread the buttercream on.

How to apply a crumb coat

Next, it’s time for a crumb coat. Before you start, chill the assembled cake for about 20 minutes in the fridge or 10 minutes in the freezer. This sets the buttercream 'glue' and holds the cake securely in place while you frost it. A cold cake is also much firmer so it won't lean as you spread and scrape around it.

Apply a thin layer of buttercream over the entire cake. I like to start with the top and then move down to the sides. This layer doesn’t need to be perfectly neat, but it’s important to avoid any bulges of buttercream sticking out sideways or above the top edge. Those will harden when chilled and can stick through your final coat of frosting. It's fine to be able to see the colour of the cake through the frosting in places, as long as there is at least a thin layer of frosting covering it. If the cake is completely exposed, those crumbs will get into your final layer of frosting, which you don't want.

Once the crumb coat is finished, chill the cake again for 20 minutes in the fridge or 10 minutes in the freezer.

How to apply the final coat for sharp edges on a cake

Now the cake is ready for its final coat, which is where sharp edges on a cake are created. First, wipe the cake board clean with a towel or paper towel. If there are any hardened smudges of buttercream, your cake scraper will bump into them as you smooth the sides, creating dents in the frosting.

Spread buttercream onto the top of the cake and push it outwards so it extends over the edges. This prevents gaps around the top edge. Then spread buttercream around the sides of the cake, making sure it sticks up above the top edge. This is crucial because it prevents a domed top and instead creates a wall or lip of buttercream all the way around the cake. See the image below for a visual on the two places the buttercream should be sticking out. Continue spreading down to the bottom so the cake is fully covered.

How to smooth the sides for sharp edges on a cake

To smooth the sides, press the base of your cake comb or scraper flat against the cake board to line it up straight. This helps create straight sides, instead of a cake that's wider at the top than the bottom (or wider at the bottom than the top). Spin your turntable and scrape around the cake in long, smooth motions. After a few scrapes, fill in any gaps or indents with more buttercream and scrape again. Repeat this process until the sides are smooth and even.

How to create sharp edges on a cake with a spatula

Now for the part you've been waiting for: the top edge. Use an offset spatula, angled palette knife, or cake scraper and swipe sideways, pushing the lip of buttercream towards the center of the cake. Then lift your tool up and away to remove the excess frosting. Wipe your blade clean after each swipe so you don’t drag buttercream back onto the surface and create texture.

Here are the three things to focus on:

• It’s important to push sideways rather than down, because pushing down will create a bulge underneath the top edge.
• Don’t swipe more than halfway across the cake before lifting your spatula. If you swipe too far you'll drag buttercream over the opposite edge.
• For your first swipe, swipe slightly higher than you think you need to. You can always go back and swipe lower, but starting too low can expose the crumb coat or even the cake itself. Trying to fix that with an upward diagonal swipe will create a domed top instead of a sharp 90° angle.

Work your way all the way around the cake and then get down to eye level and spin the cake to check that the top edge is flat and level. If you see any areas where the edge rises, go back and swipe those sections again until the entire top edge is even.

Why chilling is essential for sharp edges on a cake

The final step is to chill the cake again so the buttercream sets and becomes firm. This is essential for maintaining sharp edges on a cake. If you try to decorate the cake while the frosting is still soft, you’ll damage the smooth sides. If you pipe onto the top before chilling, the weight of the buttercream can push down and cause the edges to droop or bulge. Chilling locks everything in place so your edges stay crisp.

I hope this tutorial helps you achieve sharp edges on a cake with confidence. For more cake decorating techniques and designs, visit my cake school!

You can also watch a video of this tutorial on how to get sharp edges on a cake: