In a medium bowl, whisk together eggs, salt, and sugar.
Pour in half of the milk and gradually add flour. Keep whisking until a batter becomes thick, resembling a consistency of sour cream.
Add the remaining milk and whisk to combine.
Pour in ½ cup of hot boiling water and avocado oil.
Heat a small non-stick pan over a medium heat. Add a small amount of butter, just enough to coat the pan.
Take half a ladle of a crepe batter, pour in the center of a pan and swirl to spread evenly. Cook on one side for 2 minutes, until edges start to brown and you can loosen the edges with a rubber spatula.
Flip it to the other side. Cook for 30 more seconds or 1 minute on the other side. Transfer to a plate and cook the rest of the crepes.