This is a delicious fruit muffin. You can also use blueberries instead of the currants. You can use any gluten free flour mix suitable for cakes or muffins. The total amount of flour in this recipe is 1/2 pound. Usually I use 5 ounces rice flour, 2 ounces potato starch and 2 ounces tapioca starch. You can also use half brown rice flour or sorghum or millet for half of the rice flour. The buttermilk is 150 ml which would be 5 fluid ounces or 1/2 cup and 2 tablespoons.