1 For the cupcakes: heat the oven to 180°C (160° fan) 350°F gas 4. Grease a 12 hole muffin tin.
2 Sift the flour, baking powder and baking soda into a mixing bowl. Mix in the sugar and grated zucchini.
3 Whisk together the eggs and oil. Stir into the dry ingredients, followed by the warm, melted chocolate.
4 Spoon into the muffin tins and bake for 30-35 minutes until well risen and a skewer inserted gently into the centre of a muffin comes out clean. Cool in the tins for 5 minutes then place on a wire rack to cool.
5 For the buttercream: beat the butter until soft and creamy. Sift in the confectioners'’ sugar and beat well. Stir in the vanilla.
6 Spread the buttercream over the top of the cakes and decorate with rose petals.