Preheat oven to 350 degrees.
Line baking sheets with parchment paper.
Whisk the rice flour, cassava flour, baking powder, baking soda, and sea salt.
In a mixer, cream the butter, brown sugar, and granulated sugar until light and fluffy.
Add in eggs and vanilla and beat until combined.
Add in dry ingredients and beat to combine.
Add in oats and mix until distributed evenly.
Fold in chocolate chips.
Spoon balls of dough on to baking sheets and press down slightly.
Bake for about 12 minutes until slightly golden. Cookies will be slightly chewy. If you want a crisp cookie bake an additional 3-4 minutes.
Cool cookies on the baking sheet for about 5 minutes, then remove the cookies onto a cooling rack.