To make the sponges, preheat the oven to 180 degrees Celsius (350 Fahrenheit).
Add the butter cut into cubes and milk to a pan set over a low to medium heat.
Leave the butter to melt, and remove the milk from the pan while it's just warm, not boiling hot.
In a large mixing bowl add the eggs and sugar and use a hand mixer to beat them together until creamy.
Add the butter and milk mixture and vanilla extract, sift in the flour and baking powder, and use a spatula to mix into a batter.
Line a muffin tin with paper cases and divide the batter evenly.
Bake for 20 minutes or until golden and well risen and a skewer inserted in the middle comes out clean.
Remove the cupcakes from the oven and let them cool down completely.
To make the strawberry sauce, cut the strawberries into small chunks and add them to a pan together with the sugar.
Simmer on a medium heat until the strawberries release their liquid, then use a potato masher to mash them well.
Continue to simmer the mixture until it reduces into a jammy-like texture.
Pass the mixture through a sieve to remove any pits and bits.
Once the sponges have cooled down, beat the cream with a hand mixer until it holds soft peaks.
Add the cream to a piping bag fit with a large star nozzle and decorate each cupcake.
Drizzle the strawberry coulis over each cupcake and decorate with strawberry slices.