Preheat your oven to 350 degrees F
In a large bowl, whisk together the sifted flours (arrowroot starch and cassava to form a cake flour) baking powder, and salt.
In another small bowl, whisk together the vinegar and coconut milk. Set aside to form a buttermilk mixture and come to room temp.
In a medium bowl, beat eggs and sugar. Then add oil, buttermilk mixture and vanilla extract.
Pour the wet ingredients into the dry and mix util well combined but do not over stir.
Line a rimmed baking sheet line with parchment paper and pour in the batter
Use a spatula to smooth out the batter until it is in a thin and even layer
Bake at 350F for 15-18 minutes. Remoe from the oven and chill in the fridge while you prep your other ingredients