Heat the water to 105 - 110 degrees F. Stir in the honey. Sprinkle yeast over top and give it a stir. Set aside to proof while you prepare the remaining ingredients.
Melt the butter and set aside.
Weigh out the dry ingredients and add them to your stand mixer bowl. Add salt. Mix on low speed for a few seconds to blend ingredients together.
While mixing on low speed, pour in water and yeast mixture, melted butter, egg, and vinegar.
Increase speed to medium and mix for 4 minutes.
Spray pan with non-stick cooking spray - I use a muffin top pan to help keep the shape of the buns (since gluten-free yeast dough is more like a batter). Divide batter into 6 buns (I use a large scoop) in the pan. Wet your hands and press them down to form buns.
Allow to rise in a warm spot until nearly doubled in size.
Preheat oven to 375 degrees F. Place pan in preheated oven and bake for 22-25 minutes, until lightly browned. Allow to cool on a rack.
Notes
I make yogurt in my Instant Pot, which I strain to thicken, resulting in whey. I sometimes use the whey in place of part or all of the water in this recipe.