1. Pre heat oven to 170°C.
2. Cream the butter and sugar together until light and fluffy, then add the egg.
3. Slowly add the milk until it is all incorporated.
4. Sieve the flour, cocoa powder and bicarbonate of soda then fold into he butter mixture.
5. Line a baking tray with parchment paper and using a piping bag fill with the mix, pipe 24 x 4cm disc shapes. Leave plenty of space between discs.
6. Bake in oven for 10-15 minutes or until cooked.
7. Heat milk in a saucepan, add the marshmallows, stir until they have melted. Remove from the heat, stir in vanilla essence and Major Mango Fruit Base. Cream the butter and sugar together in a mixer with a paddle and when the marshmallow mix has cooled add it in.
8. Spoon or pipe onto half of the whoopie pie, then place another on top to form a sandwich.
9. Bring the cream and glucose to the boil, pour over the chocolate callets. Stir well until callets have melted. When warm spoon on top of whoopie pies. Decorate as desired.