To make the sponges, add the soften butter to a large bowl together with the sugar.
Use a hand mixer to cream them together until smooth.
Add the eggs one by one, mixing well after each addition.
Sift in the flour, add the milk, baking powder and vanilla extract and mix to incorporate.
Preheat the oven to 180 degrees Celsius (350 Fahrenheit).
Line a 12-hole muffin tin with paper cases and divide the batter evenly.
Bake for 20 minutes until golden and a skewer inserted in the middle of the sponges comes out clean.
Leave the sponges to cool down completely in their cases.
Once they have cooled down, peel the paper cases off, cut each cupcake in half horizontally, spread jam on one side, and top with whipped cream - I added the cream to a piping bag fitted with a star nozzle, but it can also be done with a spoon if it's easier.
Dust the cupcakes with icing sugar.