Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper to prevent sticking.

In a large bowl, combine oat flour, coconut flour, gluten-free rolled oats, baking powder, and salt. Mix these dry ingredients well to ensure even distribution.

In another bowl, whisk together the melted refined coconut oil, maple syrup, vanilla extract, egg, and egg yolk until the mixture is smooth and homogeneous.

Stir in the coconut sugar until fully integrated.

Gradually add the wet ingredients to the dry ingredients, stirring continuously to combine. The goal is to form a cohesive dough that holds together well.

Fold in the chocolate chips, ensuring they are evenly distributed throughout the dough.

Using a spoon or cookie scoop, drop dough balls onto the prepared baking sheet. You may want to gently flatten the dough balls slightly as they will not spread much during baking.

Bake in the preheated oven for about 12-15 minutes or until the edges are golden brown and the centers have set but are still soft.

Remove the cookies from the oven and let them cool on the baking sheet for about 5 minutes. Then transfer them to a wire rack to cool completely.

Enjoy your freshly baked gluten-free oatmeal chocolate chip cookies with a glass of dairy-free milk, or pack them as a treat for a day out!