Step 1

Beat the butter (250g) on a low speed until it is soft.

Step 2

Add the icing sugar (500g) and beat until combined - I like to add mine a spoonful at a time as it helps stop it flying out of the bowl!

Step 3

Finely grate the zest of 5 lemons. Squeeze the juice from the lemons until you have 1 tbsp.

Step 4

Add the lemon zest to the buttercream and beat until it is evenly distributed. Slowly add the lemon juice (no more than 1 tsp at a time) and beat in each addition before adding more.

Step 5

Check the consistency of your buttercream - It should be soft enough that you could spread it onto a slice of bread without the bread tearing, but not runny. If it is a little stiff, then add a little milk (again no more than 1 tsp at a time) until is it the right consistency.

Step 6

Your buttercream is now ready to use.