Combine the yeast, sugar and warmed milk in medium size bowl and whisk to dissolve the sugar. Let sit for 6 8 minutes or until the mixture is foamy and had increased in volume. Combine the flours, starches, xanthan gum, salt and baking powder in the bowl of an electric mixer fitted with the whisk attachment. Mix for 30 seconds on medium-low to combine and break up any lumps in the potato starch. Add the yeast mixture, eggs, butter, honey and vinegar. Mix on medium low until combined. Scrape down the sides of the bowl, turn the mixer on high and mix for 3 minutes. You should have a very thick, smooth batter. Brush 2 standard muffin pans with melted butter or shortening. Preheat the oven to 375°F. Spoon the batter into the prepared muffin pans, filling about three-fourths full. If desired, spray lightly with gluten free cooking spray or oil spritz. Let rise for 35 minutes or until the dough has almost doubled in size. Bake for 15 minutes or until golden brown. Watch closely so they don't over brown on the bottoms. Makes 18-24 rolls. Note: In place of the various flours and starches you can use 3¼ cups of a good quality, all-purpose gluten free flour blend.