Preheat the oven to 190°C /170°C fan oven/375°F,/gas 5. Line 12 cup cake tins with white paper cake cases. In a mixing bowl, beat the margarine with the sugar until pale and creamy-light in texture.
Gradually whisk in the eggs, then sift the flour and baking powder on top. Using a large metal spoon, carefully fold the dry ingredients into the eggy mixture.
Spoon a teaspoon of the mixture into the cake cases, and make a slight indent in the mixture. Spoon a little lemon curd on top and then cover with the remaining cake mixture. Bake on the middle shelf in the oven for 16-18 minutes until risen, lightly golden and just firm to the touch. Transfer to a wire rack to cool.
For the icing, place the butter in a bowl and beat until soft. Gradually sift and beat in the icing sugar to make a smooth, creamy icing. Mix in the lemon rind.
Put some 100s and 1000s in a small bowl, just larger than the size of a cup cake. Using a small palette knife, spread a generous swirl of the lemon icing over the top of each cup cake to cover it.
Carefully press the top of each cup cake into the 100s and 1000s making sure the icing is completely bejewelled in decorations.
This recipe is brought to you by Dr. Oetker baking range