1. Preheat the oven to 180°C (160°C Fan, Gas Mark 4). Line a cupcake tray with 12 Baking Cases.
2. Put the margarine, sugar, Caramel Flavour and eggs in a bowl. Sift the flour and Baking Powder on top. Using an electric whisk, beat all the ingredients together and whisk for a few seconds until well blended.
3. Spoon the mixture into the cake cases, smooth the tops and bake in the oven for 18-20 minutes until risen, lightly golden and just firm to the touch. Transfer to a wire rack to cool.
4. Using a small spoon, scoop out a piece of sponge from the centre of each cake and fill with some of the canned caramel. Replace the scooped out cake on top. Spread the tops lightly with the remaining canned caramel and arrange 4 Mini Marshmallows in a neat pyramid (3 plus 1 on top) on the top of each cake.
5. To decorate, put the vegetable fat and butter in a bowl and beat until smooth and glossy. Gradually sift and beat in the icing sugar to make a firm icing.
6. Add the Caramel Flavour and squeeze in the 2 tubes of Green Gel Food Colour. Mix well to achieve a bright green coloured icing.
7. Spoon the icing into a large piping bag fitted with a small star nozzle. Start piping as close to the edge of the marshmallows as you can and continue piping in layers upwards until the marshmallows are covered and icing forms a peak on top of the cake.
8. For a festive finishing touch, arrange the Chocolate Gold and Silver Pearls to decorate. Your cakes are now ready to serve and enjoy.