Mix together the flour, baking powder and salt in large mixing bowl. Cut in the cold butter until the mixture resembles gravel.
Add the milk and stir to form a dough. Try not to overwork the dough.
With a spoon, scoop out 10 biscuits.
Place the biscuits, spaced apart, in the basket. You may need to cook them in 2 batches, depending on the size of your air fryer.
Cook on 400° F(200°C) for 8 minutes, then open the basket and brush on the melted butter. Continue cooking until lightly golden brown on top, about 1-2 more minutes.