Learn how to cover a cake with rich buttercream icing for an impressive finish and discover the basics of cake decorating with our step-by-step video, below.


First, make sure your kitchen is stocked with the best cake decorating kit. For more, read our reviews of baking kit, including the best stand mixers, cake tins, electric whisks, cooling racks and piping bags, plus discover eight gadgets every baking lover should know about.

For more inspiration, see our ultimate showstopping cake recipes, top birthday cakes for adults and best ever chocolate cakes.

How to buttercream a cake

Wondering how to cover a cake with thick buttercream? See our how-to video for our expert tips and tricks:

  1. Spoon a large dollop of softened (but not runny or melty) buttercream onto the top of the cake. Use a spatula or palette knife to smooth the buttercream to the edge.
  2. Use the spatula or palette knife to smooth smaller amounts of buttercream over the sides of the cake in sections, then turn the cake and repeat.
  3. For a smooth finish, hold a long palette knife or ruler flat at the edge of the cake furthest from you and drag it towards you. Repeat if necessary.
  4. Hold a palette knife or plastic side scraper (available from cake-decorating websites) in one hand at a 90-degree angle to the cake. Use the other hand to gently spin the cake as you smooth the buttercream. This is easiest on a turntable, as you can do it in one movement. If not, you may need to do this in sections and smooth any joins with the palette knife.
  5. To get a feathered 'frosty' effect, simply press the flat side of a palette knife or spatula onto the cake and lift. Repeat over the entire cake.

How to make buttercream

  • Beat 600g sifted icing sugar and 300g butter together using an electric whisk or stand mixer, along with your chosen flavouring and food colouring gel, if using.
  • Add 2-3 tbsp boiling water to loosen and beat until smooth.
  • Spoon the buttercream into a piping bag fitted with a star nozzle and pipe it onto cupcakes, or simply spoon it into the middle of a cake and smooth it over the top and side as instructed above.

How to thicken buttercream

A ratio of equal quantities of icing sugar and butter works well, unless you’re adding a significant quantity of a liquid like lemon juice or melted chocolate.

More like this

If you are, you can increase the quantity of icing sugar, adding as much as double the stated amount. Add it gradually – making sure it's sifted first – until you get the consistency you want.

How to store buttercream

If you’re not using the icing straightaway, it can be covered and chilled for up to a week. Let it come to room temperature and beat again if needed before using.

How much buttercream to make

  • 10cm (4in) cake: 150g buttercream
  • 13cm (5in) cake: 225g buttercream
  • 15cm (6in) cake: 300g buttercream
  • 18cm (7in) cake: 450g buttercream
  • 20cm (8in) cake: 600g buttercream
  • 23cm (9in) cake: 750g buttercream
  • 25cm (10in) cake: 900g buttercream
  • 28cm (11in) cake: 1.2kg buttercream
  • 30cm (12in) cake: 1.5kg buttercream

See more beautiful bakes:

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Our guide to classic cakes
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