In a large bowl, whisk together the gluten-free baking flour, baking powder, baking soda, kosher salt, and granulated sugar.

Cut the very cold vegan butter into small cubes. Add to the dry ingredients and cut in with a pastry blender or your fingers until the mixture resembles coarse crumbs with some pea-sized pieces of butter remaining.

In a separate bowl, whisk together the homemade vegan buttermilk, full fat coconut milk, and maple syrup.

Pour the wet ingredients into the dry ingredients. Mix gently with a spatula until just combined. Be careful not to overmix; the dough will be shaggy.

Turn the dough out onto a lightly floured surface. Gently knead 3-4 times, then pat into a 1-inch thick rectangle. Fold the dough in thirds (like a letter), then pat down again. Repeat this folding and patting 2-3 more times to create layers. Cut into desired biscuit shapes using a biscuit cutter or knife.

Place the biscuits on a parchment-lined baking sheet. Bake in a preheated oven at 425°F (220°C) for 15-18 minutes, or until golden brown on top and cooked through. Brush with melted vegan butter immediately after removing from the oven.

Serve warm and enjoy immediately.