Combine in a blender or immersion blender, the milk and eggs. Then add in the four and salt. Mix until combined, but do not overmix.
Place little cubes of butter in each silicone muffin liners. Place in the air fryer basket. Run the air fryer for 1-3 minutes at 330 °F, or until the butter is melted. Do not let the butter burn.
Pour in batter to each liner until it is about half way full.
Air fry at 330 °F for 5-7 minutes, or until they are all puffy and internal temp is around 200 °F.