• Preheat the oven to 180'C (170'C fan) / Gas 4. Grease and line three 20cm/8-inch diameter round baking tins.
• Add the butter, sugar and vanilla extract to a large mixing bowl and beat with an electric whisk until pale and creamy. (TIP: If the butter is hard, zap it in the microwave for 10-15 seconds before adding it to the mixing bowl to make it easier!
• Crack the eggs into the mixing bowl and beat again for 30 seconds to combine. Scrape down the sides of the bowl using a spatula.
• Sift in the self-raising gluten free flour and xantham gum, add the milk, and then beat together with the electric whisk until everything is fully combined. You want a fairly thick batter which looks light and fluffy.
• Add the sprinkles to the mixture and fold in with a spatula - just enough to ensure they're evenly distributed. Don't over-mix as you don't want them to start leaching their colour into the cake batter.
• Divide the mixture evenly between the three cake tins and smooth out with a spatula so they are level. Bake for 30-35 minutes until golden and well-risen. To test, a skewer inserted in the middle should come out clean.
• Remove the cakes from the oven and cool completely on a wire rack before decorating.

To make the frosting:

• Add the butter, icing sugar, milk and vanilla extract to a large mixing bowl and beat with an electric whisk on a low speed until it becomes a smooth, pale buttercream. (TIP: To avoid an icing-sugar dust cloud I tend to 'mash' the mixture with a fork until it starts to come together, then use the electric whisk).
• Spoon the mixture into a piping bag with a large round tip.

To assemble:

• Turn the cakes carefully out of the baking tins and remove any baking paper. Place the first sponge onto your chosen cake stand. Pipe the frosting onto the cakes - I like to do this in 'blobs' as pictured as it looks really effective!
• Once the first layer is all piped on, place the second tier on top and repeat. Repeat again with the third tier and decorate with sprinkles before serving.