1. Cream together the butter and sugar until the mixture is light and fluffy then one at a time beat in the eggs followed by the condensed milk then lime zest and juice.
2. Sift the flour, polenta and baking powder into the cake mixture, folding in with either a spatula or metal spoon. Fold in the poppy seeds ensuring they are evenly distributed.
3. Divide the mixture between 32 medium sized paper cupcake cases then bake for 15 - 20 minutes in the pre-heated oven until risen, a light golden colour and the sponge springs back when lightly pressed. Cool on a wire rack.
4. Beat together the topping ingredients, generously spreading over each cupcake.