Special equipment: A Belgian waffle iron
For the gluten-free flour blend: In a large bowl, whisk together the rice flour, tapioca flour, potato starch, xanthan gum and salt.
For the waffles: In another large bowl, whisk together 1 1/2 cups of the gluten-free flour blend, sugar, baking powder and salt. (Reserve the remaining gluten-free flour blend for another use.)
Preheat a Belgian waffle iron to medium-high and grease with gluten-free cooking spray. In a small bowl, whisk together the milk, eggs, oil and vanilla; stir into the flour mixture until combined. Stir in the chocolate chips, then lightly fold in the cookie crumbs.
Pour a heaping 1/3 cup of batter into each waffle iron square, pushing the batter out to the edges; scatter over some of the larger cookie pieces. Close the waffle iron and cook until crisp, about 4 minutes. Cook the remaining waffles and top with whipped cream, chocolate syrup and more cookie pieces.