This is a post that explains how I spread buttercream frosting and chocolate ganache on to cakes so it’s (nearly!) perfectly smooth – on both top and sides!
Smooth buttercream frosting or ganache on cakes
There are various reasons why you might want a perfectly smooth frosting on a cake. Maybe you’re simply wanting a pristine, smooth cake surface for your cake decoration. Or perhaps you need an immaculately even base for a flawless Mirror Glaze.
So today I’m sharing how I do it. Yes, I will be pulling out some speciality cake decorating equipment. But no, they aren’t essential. They just help to frost cakes faster.
So don’t worry if you don’t have all the equipment listed – I provide alternatives that I used to use myself up until a few months ago!
What frosting to use
Both buttercream and chocolate ganache are suitable for this tutorial. For the buttercream frosting, you can use any flavour you want, as long as it has enough structure – ie. not too loose. Both my Chocolate Buttercream and Vanilla Buttercream recipes are suitable for this tutorial. (Note the Vanilla Buttercream is in the Vanilla Cake recipe).
What cake to use
You can use any cake you want. I’m using my Chocolate Cake with a dark chocolate ganache in this tutorial because it’s an elegant, classic combination. Especially once finished with a Mirror Glaze – which is why I want a smooth surface on this cake! And the, ummmm, “icing on the cake” (yeah I went there): The cake is a dead easy one-bowl miracle creation that’s intensely chocolatey, ultra-moist and has a long shelf life.
My classic Vanilla Cake pictured below would also be ideal. Bonus: You are unlikely to need to level it because it comes out near perfectly flat!
Part 1: Frosting the cake
- Level the cake – just slice off the mounded top of each cake using a serrated knife. Using the side of the cake as a guide, it’s honestly easier to eyeball it rather than fussing with cake levellers;
- Flip the cake upside down to frost it, so you’re working with a nice level surface. Use a cake spinner if you’ve got one because it will make frosting faster, but it’s not essential. I’ve been frosting cakes all my life without one up, until 2 weeks ago! (PS This is the one I got – very sturdy and non slip which is what you want. No point getting a rocky cheap plastic one. Here it is on Amazon US. These are not affiliate links.)
- Pipe on the chocolate ganache in a swirl – this is the easiest, fastest way to frost a cake so it’s nice and level. Trust me – dolloping a giant scoop of ganache on the cake is much harder!!
- Spread the top ganache to fill the gaps. No need to be perfect here because it’s the filling layer and will get levelled/squished when you put the next cake layer on.
5. Top with next layer then pipe ganache all around the sides, from the base right up to the top edge;
6. Pipe ganache on surface in the same coil pattern, right to the very edge;
7. Smooth roughly – use a small palette knife (or butter knife) to smooth it out but don’t bother trying to make it ultra smooth at this stage. We’re going to refrigerate it to make the ganache easier to work with to make it beautifully smooth 👍🏼
8. Refrigerate for 1 hour to make the ganache firmer – this will make it much easier to make it smooth!
Part 2: Making it smooth!
- Smooth surface – Remove the cake from the fridge. If you refrigerated overnight or for hours, then let it soften for 5 to 10 minutes before working with it. Then use a a combination of large and small palette knives, or really anything flat and fairly long so you can swipe it across the surface of the cake to level it out as best you can. I use a combination of a large and small palette knife. The large is good for big surface area levelling, but the small one is much easier to work with for better control;
- Smooth sides – Smooth and straighten the side of the cake using a cake scraper, if you have one. Otherwise use anything with a straight edge – I used to use a ruler 😂 (it still works!);
- Tidy corners – run a small palette knife lightly around the rim on a 45 degree angle, then smooth this out on the surface and side of the cake. This is also your chance to ensure the cake is perfectly round from overhead.
- Check at eye level – The best way to check how smooth and level your cake is by looking at it from the side.
KEY TIP: The easiest way to make the sides and surfaces smooth is when the buttercream or ganache is slightly on the firm side, cold out of the fridge. So if you handle it for too long and it starts getting soft again, just pop it back in the fridge briefly.
The time it takes for the ganache or buttercream to get too soft to work with depends on how warm your kitchen is – it can be 10 minutes in winter to 3 minutes at the height of summer inside my house!
Part 3: Moving the frosted cake
Here’s how I move cakes neatly when I need to take extra care – using two palette or kitchen knives. The example shown below in the step photos and in the video is a Mirror Glaze Cake:
- Palette knives or kitchen knives – Use either 2 long palette knives or 2 kitchen knives (or one of each, as I do!). Slide them under the cake about 1/4 of the way through – one from the left and one from the right;
- Lift them at the same time then move the cake onto the rack/platter;
- Push off with a 3rd knife – Once the cake is on the rack/platter, leave the shifting knives in place under the cake. Now get a butter knife or small palette knife to help slide each of the shifting knives out neatly without making the ganache/frosting/mirror glaze untidy; and
- Voila! Tidy edges! (That’s just a smear on the cake platter you see in the above step photos.)
And there you have it. Now you have a beautiful cake with smooth frosting or chocolate ganache, ready to decorate as you wish!
Oh – and I can’t sign off without giving you a little preview of that Mirror Glaze in action….
It seems strange to write a post without inserting a recipe, but there doesn’t seem to be much value in writing out the above steps in a recipe card.
Perhaps I’m wrong. If you want me to abbreviate the steps in a recipe card – perhaps even with the photos – drop a message below and I’ll do it! – Nagi x
Life of Dozer
This is not one of his cuter habits (it’s a really windy, blustery cold day today and it’s blasting into the house!).