Pre-heat the oven to 160C / 325 F
Using an electric mixer, combine the flour, cocoa, salt, baking soda, and brown sugar in a bowl. Beat in the egg, vanilla, and butter on a low speed until well combined. Add the beer and briefly mix until it’s incorporated. Do not overwork the batter.
Spray a doughnut pan with cooking spray and scoop the batter into a pastry bag fitted with a wide round tip. Pipe this into the doughnut pan filling it about ¾ of the way up.
Bake for around 12 minutes until firm to the touch and when a skewer is inserted it comes out clean. Cool in the pan slightly and then transfer to a cooling rack.
Repeat with the second batch of batter as this recipe makes between 22 – 24 doughnuts.
Ps: if you only have one pan, washing it between bakes cools it down.
To make the glaze mix all the ingredients together in a bowl until well combined. Dip the doughnuts in the glaze scraping off any excess. Allow them to drip on a wire baking rack with a tray underneath to catch any excess. Decorate with your sprinkles right away and then allow the glaze to harden slightly.
*tip: to give the glaze a richer stout flavour, substitute 1 – 2 Tbsp of the milk for Castle Chocolate Milk Stout