These delicious, tangy key lime cupcakes are simple to make and have a soft, citrus-infused moist sponge and a light and creamy Swiss meringue buttercream on top – a great spin on a classic dessert recipe. These tasty treats are perfect for parties or as a sweet gift for friends and family. You could try this recipe with lemon curd or other flavours once you’ve perfected this recipe. Sprinkle with green sugar strands to complete the look and serve on a large serving plate so they get the attention they deserve.
- For the cakes:
- 150g butter
- 150g self-raising flour
- 175g golden caster sugar
- 2 large eggs
- 3tbsps milk
- 3tbsp lime juice
- Zest of 2 limes
- ¼tsp baking powder
- 12tsp key lime curd
- Neon decorating sugar
- For the Swiss meringue buttercream
- 4 egg whites
- 225g granulated sugar
- Pinch of salt
- 300g unsalted butter, cubed
- 1/2 tsp vanilla bean paste/extract
- You will also need:
- Deep Muffin pan with 12 cupcakes cases
- Apple corer and zester
- Piping bag with a Wilton 2A Nozzle (optional)
For the cakes:
- To make this cupcake recipe, preheat the oven to 160°C/325°F/Gas Mark 3 and line your muffin tray with cases
- Add the lime juice to the milk and leave to one side.
- Beat the butter and sugar together until light in colour, add the eggs, sifted flour, baking powder and beat again. Add the lime zest, milk and lime mix and beat again until just combined.
- Divide the mixture between the 12 cases and bake for 30 minutes. Remove from the oven and cool in the tin for 5 minutes before moving onto a wire rack.
- When the cakes are cool, remove the centre from the cakes with an apple corer. Add one teaspoon of key lime curd to each cake the replace the sponge centre.
For the Swiss meringue buttercream:
- Add the egg whites and sugar to a large heat proof bowl and heat over a pan of boiling water, making sure the water doesn’t touch the bowl. If you have a sugar thermometer the sugar will be dissolved when it gets to between 140-160°F or when it doesn’t feel gritty anymore.
- When the sugar has dissolved transfer to a stand mixer bowl – stand mixers are good for this but not essential. Whisk the sugar and egg white until you have stiff peaks. Once you have stiff peaks and the bowl is cool to touch, add in the butter one cube at a time and mix until all the butter has been mixed in. It may look like the buttercream has split at one stage, this is normal, keep beating until you hear a slapping sound (about 8 minutes), this means it’s ready. Add the vanilla extract and the salt and beat until mixed evenly through the buttercream.
- To pipe a swirl use a Wilton 2A nozzle and a piping bag or use a palette knife to spread the buttercream onto the cupcakes. Decorate with the neon sugar and a slice of lime.
Top tip for making Key lime cupcakes
When making the Swiss meringue buttercream, it helps to clean everything you are using (bowls, spoons, whisks) in lemon/lime juice first as this eliminates any grease. Also using a metal whisk instead of a silicone will help too.