Pre-heat oven to 160C (fan forced)

For the biscuits

Place butter and brown sugar in a large bowl and beat with an electric mixer until smooth. Add egg and vanilla and mix well. Fold in sifted flour. Place mixture on a lightly floured surface and roll out to 5mm thickness. Cut out 16 circles with a 6cm round biscuit cutter and place on a lightly greased oven tray. Bake for 10-12 minutes or until golden and cooked. Cool on trays.

For the marshmallow

Combine caster sugar and water in a small saucepan, then sprinkle gelatine powder into the mix. Stir over low heat until sugar and gelatine dissolve. Bring to the boil, then reduce heat and simmer for 4-5 minutes. Remove and cool. When almost cold, pour mixture into a bowl, add vanilla and beat with an electric mixer for 3-4 minutes until mixture is very thick.

To assemble

Spoon marshmallow mixture into a piping bag fitted with a 1cm plain tube and pipe marshmallow around the edge of half the biscuits. Spoon a little jam into the centre of the marshmallow and top with remaining biscuits, pressing gently. Rest biscuits in fridge for about 15 minutes until marshmallow is firm then place on a cake rack and spread with melted chocolate.

Store in an airtight container.