Preheat the oven to gas 6, 200°C, fan 180°C. Line a 12 muffin tin with paper cases or lightly butter the tin if you aren't using cases.
Sift the flour and cocoa powder together in a large mixing bowl. Mix in the sugar. Melt the butter, cool and beat in the egg. Add the buttermilk, honey, orange juice and zest and mix together.
Pour the mixed liquid ingredients into the dry ingredients and stir until combined. Don't over mix as the mixture will become heavy. Distribute the mixture between the muffin tins.
Bake in the oven for 20 minutes until the muffins are firm to the touch. Test that they are cooked with a skewer which should come out clean.
Remove from the oven and allow to cool before garnishing with slivers of orange peel, dusting with icing sugar and serving.