Preheat oven to 350°F/175°C. Grease a donut pan with butter or baking spray.
Whisk together the flour, sugar, cocoa powder, nutmeg, baking powder, baking soda, and salt in a large bowl. Combine buttermilk, eggs, melted butter and vanilla extract.
Pour buttermilk mixture into dry mixture and fold in until all incorporated. Make sure there are no flour pockets.
Pipe the batter into the cavities, filling each ¾ of the way. Bake for 11-13 minutes, until golden brown and springy to the touch. After 5 minutes take out each donut and let cool on a wire rack, before pouring the next batch in. I like the re-grease the pan before I refill it.
Vanilla Glaze
Combine all ingredients together in a medium bowl until completely smooth. Dip each cooled doughnut in and let dry on a cooling rack above a paper towel.
Notes
My recipes have been developed and tested in metric grams. I highly recommend using a weighing scale and measuring out your ingredients the metric way. I have provided a conversion to US cups but please note that I haven’t tested the recipe with this method.Butter: I use European style butter, like Kerry Gold, in my recipes. Salt: If you don’t have kosher salt, halve the amount of salt called for in the recipe. 1 teaspoon kosher salt = ½ teaspoon fine salt.Buttermilk: No buttermilk on hand? You can substitute it for sour cream.Storage: Keep the donuts in an airtight container and keep in the fridge for up to 3 days. You can freeze the donuts for up to 3 months, let them defrost overnight in the fridge before eating.