Prepare the flax egg by mixing the ground flax seeds and the warm water. Let it sit for 5 minutes.
In a mixing bowl, combine the oat flour, rice flour, arrowroot powder and a pinch of salt (see step-by-step pictures in post above).
Create a "well" in the center of the dry ingredients. Add in the flax egg, coconut sugar and almond milk. Whisk until the crepe batter is lump-free.
Heat a crepe or non-stick pan with vegan butter over medium-high heat. Once the butter is melted, add it to the crepe batter and give it a good mix.
Add a drop of batter to the pan. When it sizzles and sets very quickly, the pan is hot enough.
Pour a ladle of batter into the pan and quickly rotate it to spread it out as thinly as possible. Let it cook for 2 minutes or until the edges start to lift.
Flip the crepe with a spatula and let it cook for another minute. Transfer the crepe to a plate (see notes).
Repeat the process until there's no batter left.