In a medium bowl, cream the butter and sugar. Slowly fold in the eggs, mix well, after each egg, slowly fold in the buttermilk, and vanilla extract.
In a separate bowl, add the flour, baking powder, baking soda, Kosher salt, ground nutmeg and ground cinnamon, mix well.
Grease a cake pan or loaf pan that fits into your air fryer basket with non-stick spray or butter. Pour the batter into the prepared cake pan, smoothing the top with a spatula.
Place the cake pan in the air fryer basket. Set the air fryer temperature to 320 degrees F, set the cook time for 15-25 minutes or until a toothpick inserted into the center comes out clean. If the top starts to brown too quickly, cover it loosely with aluminum foil to prevent burning.
Allow the cake to cool in the pan for a few minutes before transferring it to a wire rack to cool completely. Slice and enjoy your keto pound cake as a delicious, low-carb treat!