Preheat the oven to 210 °C (410°F)

In a bowl, add the white rice flour, tapioca flour, potato starch, brown rice flour, xanthan gum, baking powder, salt, sugar, and milk powder. Using a whisk, combine the ingredients. Then add the large chunks of butter. Work the butter into the flour using a pastry cutter, fork, or hand until the butter is pea-size.

Immediately, add the cold buttermilk and combine using a spatula.

Dust the working surface, your hands, and a rolling pin with gluten-free flour. Form the dough into a ball, and gently roll it into a 2 cm (¾ inch) thick rectangle. Then take one side of the dough and fold it into the center, then take the other side and fold it into the center. Then, roll the dough again into a 2 cm (¾ inch) thick rectangle. Repeat this step two more times. This will ensure that the buttermilk biscuits are flaky.

Using a cookie-cutter, press down onto the dough. Ensure that you don’t turn or twist the cookie-cutter as this can seal off the edges and prevent the biscuits from rising. Repeat until you are out of dough. You might need to collect the scraps and form a rectangle again. In the end, you should have about 7-8 buttermilk biscuits.

Brush the top of the buttermilk biscuits with melted butter or buttermilk.

Bake the buttermilk biscuits for 17-20 minutes or until the edges are golden.