Heat and combine the wet ingredients: Heat the milk and buttermilk on the stove or microwave until just warm. Melt the butter or shortening in a separate bowl or pan. Add the warmed milk and buttermilk to the melted butter and whisk well to combine
Prepare the dough: Whisk the dry ingredients together in a bowl. Add in the warmed wet ingredients.
Knead the dough: Use your hands or a handheld or stand mixer with a dough hook attachment to knead the dough Leave the dough to rise: Cover the dough with plastic wrap and leave to rise for between 45 and 60 minutes in a warm, draft-free area of your kitchen.
Punch down the dough : After the dough has risen, punch it down and turn it out of the bowl onto a well-floured surface. Knead for 1 minute.
Roll out and shape the dough: Use a rolling pin to roll out the dough to about 1 inch (2 cm) thick. Watch the video below for a visual estimate. Cut the dough with a cookie or doughnut cutter. Place doughnuts onto a baking sheet, then lightly cover and allow to rest for 5 minutes.
Bake: Preheat your Air Fryer to 350°F (176°C). Spray Air Fryer basket with cooking spray. Gently transfer doughnuts to the Air Fryer basket in a single layer. Bake until golden brown, about 5 to 10 minutes. To check the ideal temperature and time for baking these doughnuts it is best to bake a test doughnut. Air fryers vary in time and temperature and some may require longer or shorter cooking. I bake the doughnuts for between 5 to 10 minutes depending on the size of the cut doughnuts.
Frost or decorate as you prefer.