Place the margarine, sugar and lemon rind in a mixing bowl and beat till light and fluffy.
Gradually add the eggs, whisking well. Add 2 tbsp of flour with the last egg to prevent curdling.
Add the rest of the flour, whisking on a slow speed. Add 2 tbsp of hot water.
Spoon into bun cases so that each is half full.
Level and bake for 20 minutes.
Leave to cool for 5 minutes.
Combine the elderflower and lemon juice and pour over the cupcakes, then sprinkle with the remaining 2 tbsp of sugar to farm a crunch top.
To decorate, make a butter icing mix by creaming the margarine and icing sugar until light and fluffy, then add the vanilla essence and mix for another few minutes.
Smooth the butter icing over the top of the cupcakes then take some mini marshmallows and cut them diagonally to form 'flower petals'. Arrange them around the cake and finish with a sprinkle of silver crispies in the centre.