Whisk together the dry ingredients in a large bowl.
Add the cold butter cubes and use a pastry cutter or your hands to break apart the butter and work into the flour mixture until pea-sized pieces form.
Pour the chilled buttermilk over the flour-butter mixture and mix together just until combined. Do not over mix.
If the dough seems overly dry, you can add a splash more of buttermilk or if it is too wet you can add a tablespoon more flour.
Add dough to a floured surface and gently pat into a disc that is about 3/4 inch thick.
Use a 2-3 inch round cutter to cut into biscuits. DO NOT TWIST THE BISCUIT CUTTER. Just press down and pull up. Twisting the biscuits will seal the biscuit edges and they won't be able to rise.
You can take the scraps and press together to cut some additional biscuits.
Add biscuits to the air fryer in a single layer, you may need to work in batches depending on the size of your air fryer. The biscuits should be close together. This helps them rise tall.
Cook at 325F degrees for 13-15 minutes until golden brown and fluffy.
Repeat with remaining biscuits, if needed
Serve with butter, honey, or your favorite jam.
Notes
The key to this recipe is to keep the biscuit dough cold.
Don't throw away your extra dough, pat it back out to make more biscuits.
Do not twist the biscuit cutter when making biscuits. Just press down and pull up. If you twist the cutter, the biscuits won't rise because you've sealed off the edges by twisting.
You may need to make these in batches as you do not want to overcrowd the air fryer.
You can brush these with butter or even honey after they have been cooked.
If you don't have buttermilk you can make your own by adding 1 cup milk + 1 Tbs white vinegar and mixing and letting sit for 5-10 minutes. There really is no perfect substitute for real buttermilk though.