Pre-heat oven to 180 degrees C

1. Cream together the butter, sugar and orange zest until light and fluffy. One-by-one beat in the eggs.

2. Sieve the flour, polenta and baking powder into the mixture and fold-in using a spatula followed by 2tbs orange juice.

3. Line a muffin tin with 12 paper cases and divide the mixture between them then bake in the pre-heated oven for 25 minutes until risen, golden and firm to touch. Cool on a wire rack.

4. Gently cream together the frosting ingredients and casually spread over each cupcake. Decorate with a tender rosemary leaf.