Pour boiling water over raisins and currants. Let it sit to soak and allow the temperature of the water to come down to 110°F to 115°F, about 15 minutes. You'll need to save the water.
Line a 9" X 13" (22.6 X 33 cm) baking pan with parchment paper.
Whisk the dry ingredients together in a mixing bowl.
Add raw sugar to the bowl of a stand mixer. Drain the liquid from the soaking raisins and currants into the bowl with the sugar. Give it a stir or a swish to dissolve at least some of the sugar. Checking to make sure that the temperature of this liquid is no higher than 115°F, sprinkle the yeast over it, and let it sit for about 5 minutes.
Beat the yeast mixture in the stand mixer with mixing paddle on slow speed for a few seconds, just to blend it. Then add the eggs, and beat well.
Add the about half of the dry mixture to the wet. Beat together until combined, stopping to scrape down the sides as necessary.
Add the oil and vinegar. Beat. Add the remaining dry ingredients and mix them in.
Stir the raisins and currants into the batter by hand.
Shape batter into 12 balls and place, evenly spaced, into the prepared pan.
Smooth out the tops of buns with an oiled spatula. Allow the buns to rise in a warm place until a little bigger in size, about an hour.
Bake in preheated 350°F oven for 25 - 30 minutes, only until the internal temperature measures 190°F. Allow to cool completely on a rack before adding icing.
Warm the honey, either in a saucepan over low heat, in an oven proof container in a toaster oven, or in a microwave.
With a pastry brush, brush warm honey over the tops of the buns.
Beat butter and coconut oil together with a hand mixer until light and fluffy. Beat in the honey, vanilla, and salt. Then beat in the tapioca flour.
Cut a small corner (¼-inch across) from a plastic sandwich bag. Transfer the icing into the bag.
Squeeze the icing in lines across the rows of cooled buns to form crosses. It's easier to do whole rows rather than one bun at a time.
Batter for gluten free dough tends to be softer than that for regular baking. You should be able to scoop the dough into little mounds to rise, but they will be very soft.
Be careful not to over bake your hot cross buns, as they could become too dry.
The icing ingredients need to be at a warm room temperature. Both the butter and coconut oil should be soft but not runny.
Although you can use white rice flour in this recipe, brown rice flour is preferable.