¼cup (60ml) fresh lemon juice(approximately 1 large lemon)
¾cup (185ml) milk
½cup (125ml) canola oil
1cup (200g) caster sugar
For the Swiss meringue buttercream
5large egg whites
1½cups (300g) caster sugar
2cups (1lb/450g)soft unsalted butter
2tsplemon zestfinely chopped
Pre-heat the oven to 180ºC/350ºF and line muffin pans with cupcake liners/baking cases.
Whisk the flour, salt and baking powder together in a large mixing bowl.
Combine the milk and lemon juice in a measuring jug then allow to thicken before whisking in the oil, lemon zest, sugar and eggs.
Pour the wet ingredients into the dry and whisk until just combined.
Scoop the batter into the prepared baking cases and place in the oven.
Bake for 15-20 minutes or until the cupcakes are golden brown and a skewer inserted comes out clean.
Remove from the oven and allow to cool completely before frosting.
To make the Swiss meringue buttercream, combine the egg whites and sugar in a glass/metal bowl and set over a pan of gently simmering water. Whisk continuously until the sugar has dissolved. To test, rub some of the mixture between your fingers. If you don't feel any graininess, the sugar has dissolved. If it's still grainy, just keep whisking until the mixture is smooth.
Transfer egg whites to the bowl of a stand mixer and whip with the whisk attachment until thick, voluminous and cooled to room temperature. It's very important for the egg whites to be cool before adding the butter as the butter will melt and cause the mixture to become soupy if the egg whites are too hot.
When the egg whites are cool, add the soft butter one tablespoon at a time until it has all been incorporated. Switch to the paddle attachment and add the lemon zest. Beat for 1-2 minutes until smooth and creamy then transfer to a piping bag and decorate the cooled cupcakes.