Preheat the oven to fan assisted 160C / 180C / 350F / gas 4 and lightly oil a 6 cup doughnut tin.

Combine the flour, sugar, matcha, baking powder and salt in a large bowl and set aside.

In another bowl, combine the buttermilk and egg before mixing in the melted butter.

Mix the wet ingredients into the dry ingredients and stir until everything is just combined.

Using a spoon, add the batter in the doughnut cups until they are about three quarters full.

Bake the doughnuts for 13-15 mins or until a toothpick comes out clean, remove them from the oven and let them cool in the pan before transferring them to wire rack to cool completely.