Whisk together white rice flour, sweet rice flour, cornstarch, baking soda, and salt in a small bowl.
Combine melted butter, sugars, egg, egg yolk and vanilla extract in a large bowl. Stir until smooth. Add the flour. Using a wooden spoon, stir together until a dough forms. Add chocolate chips and stir until just combined.
Bake for 15-18 minutes or until golden brown. Cool cookies on a wire rack. Store in an airtight container for up to five days.