Preheat oven to gas 4 / 180C / 350°F and line 2 cupcake tins. This recipe makes 18 cupcakes

Add the vinegar to the milk and set aside for 5 minutes at room temperature

Sift the flour into a bowl and add all of other dry cake ingredients

Mix the milk, oil/apple sauce and vanilla together and whip up until frothy then add to the dry ingredients and beat until combined

Pour the mixture into the cupcake cases until 2/3 full, then bake for 25 minutes or until a skewer inserted in the centre comes away clean

While the cakes are baking, mix the custard ingredients together and bring to boil in a small pan, stirring continuously until thickened. Pour into a bowl, cover until cooled, then chill in fridge a while

When the custard has chilled completely, put it in a piping bag and pipe a swirl on top of each cake

Enjoy!