Preheat oven to 190C. Line a baking tray with baking paper.

In a bowl, sieve together flour, baking powder and cocoa, set aside.

Using an electric mixer, beat butter, then add sugars and beat again until light and fluffy. Add egg, mix well and then the buttermilk, vanilla and flour mixture and beat to form a smooth dough.

Roll 1 tbsp balls of dough and place on baking tray about 4 centimetres apart, pressing down with two fingers to form slightly rounded mounds.

Bake 10-12 minutes, until slightly firm to the touch. Cool on a wire rack. When cool, fill with salted caramel (see below) and whipped cream.

Salted caramel

Melt 200g sugar in a large, heavy saucepan over a medium heat, stirring gently until completely melted.

In a separate saucepan, warm 200ml cream and carefully add to sugar a little at a time.

Turn to a low heat. Stir in ½ tsp fleur de sel or other good-quality salt and 1 tsp vanilla extract or essence.

Cut 140g unsalted butter into cubes and add one cube at a time to mix, stirring well between each addition. Mix until caramel is smooth and glossy.

Pour into two small sterilised jars with lids and chill. Use to fill whoopie pies (see above) or spoon over ice-cream.