Preheat the oven to 200C/180 Fan
150 grams plain flour, 25 grams cocoa powder, 2 teaspoon baking powder, 1/4 teaspoon salt
Sift the flour, cocoa powder, baking powder, salt and chocolate chips into a large bowl, use a spoon or dry whisk to ensure they are well mixed.
50 grams butter
Melt the butter in a bowl in the microwave or in a small saucepan on the stove.
1 large egg, 40 grams caster sugar, 125 millilitres buttermilk
In a separate bowl mix together the egg, sugar, buttermilk and melted butter.
Pour the wet ingredients onto the dry ingredients.
Take a large spoon and fold the dry ingredients into the wet ones - quickly, in about 15 seconds.
Don't be tempted to beat or stir, and dont be alarmed by the rather unattractive, uneven appearance of the mixture: this is what will ensure that the muffins stay light.
Use a large ice cream scoop to divide the mixture between the muffin cups.
Bake on a high shelf in the preheated oven for 10 minutes, until well risen.
Remove the muffins from the oven and cool in the tins for 5 minutes before transferring them to a cooling tray.
30 grams milk chocolate
When the muffins have cooled. Melt the milk chocolate in a bowl the microwave or in a bowl over a pan of simmering water.
30 grams dark chocolate
Chop the remaining dark chocolate into small pieces.
Drizzle the melted chocolate over the muffins and scatter over the chopped chocolate or chocolate chips. Leave to cool and set.