It's best to make the toppers a day or so before so that they have time to dry. Dust the icing sugar over the counter and roll the sugarpaste to a thickness of about 5mm. Cut out the numbers and place on a baking sheet covered with greaseproof paper. Brush away excess icing sugar, or spray with vodka to remove. Leave to dry. Do not put in the fridge (they get sticky) or leave in the kitchen to dry as it's often too humid.

Preheat oven to 175C/Gas 4.

Place 24 cupcake cases into tins.

Put all of the ingredients into a mixing bowl and beat with an electric whisk for 3 minutes until smooth, pale and fluffy.

Divide the mixture between the cupcake cases. (see notes above)

Bake for 20 minutes until golden and risen.

Leave to cool in the tin for a few minutes and then transfer to a wire rack to cool completely before decorating.

To make the buttercream. Add the softened butter to a large mixing bowl and beat with an electric mixer.

Slowly sift in the icing sugar until combined.

Whisk in the milk (or lemon juice) and vanilla extract.

Divide the mixture and add a few drops of food colouring to your desired shade.

You should find that the buttercream will form stiff(ish!) peaks and can be used in a piping bag.

To assemble. Only decorate the cupcakes when they are completely cool.

Place some of the buttercream icing into a piping bag with a star nozzle attached (don't overfill the bag) and pipe a swirl on top of each cupcake.

Add sprinkles and the '30' toppers