Make the Raspberry Filling: In a small saucepan, combine the fresh raspberries, 1 tbsp of caster sugar, and 1 tbsp of lemon juice. Heat over a medium-low heat, stirring occasionally. Let it simmer gently for 5-7 minutes, crushing the berries with the back of a spoon, until the mixture has thickened into a jam-like consistency. Remove from the heat and set aside to cool completely.

Prepare for Baking: Preheat your oven to 180°C (160°C Fan) and line a 12-hole muffin tin with paper cupcake cases.

Cream the Butter and Sugar: In a large bowl, or the bowl of a stand mixer, beat the softened butter and caster sugar together until the mixture is pale, light, and fluffy. This usually takes a good 4-5 minutes and is a crucial step for a light sponge. For a deeper understanding of this technique, BBC Good Food has an excellent guide.

Combine Wet and Dry Ingredients: Add the eggs one at a time, beating well after each addition. If the mixture looks like it might curdle, add a tablespoon of your flour. Gently fold in the self-raising flour, baking powder, and lemon zest. Finally, mix in the milk and vanilla extract until you have a smooth batter. I find that it’s best to stop mixing the moment everything is just combined to avoid a tough cake.

Bake the Cupcakes: Divide the batter evenly between the 12 cupcake cases, filling each about two-thirds full. Bake in the preheated oven for 18-20 minutes, or until the sponges are golden, well-risen, and a skewer inserted into the centre comes out clean.

Cool and Core: Leave the cupcakes to cool in the tin for a few minutes before transferring them to a wire rack to cool completely. Once fully cooled, use an apple corer or a small knife to carefully remove a small circle from the centre of each cupcake, making sure not to go all the way to the bottom.

Fill the Cupcakes: Spoon the cooled raspberry filling into the hollowed-out centres of each cupcake.

Make the Buttercream: In a large bowl, beat the softened butter until it's very smooth. Gradually add the sifted icing sugar, mixing on a low speed to start (unless you want a sugar cloud in your kitchen!). Once incorporated, add the lemon zest and 2 tbsp of lemon juice and beat on high speed for 3-5 minutes until the buttercream is light and airy. Add the milk and more lemon juice if needed to reach a smooth, pipeable consistency.

Decorate: Transfer the buttercream to a piping bag fitted with your favourite nozzle (a star nozzle works well) and pipe generous swirls onto each cupcake. Garnish with a fresh raspberry and a little extra lemon zest before serving.