Grease a 9 x 13 glass baking dish with butter and set aside.
Add the milk, butter, and honey to a small saucepan and warm over medium-low heat. Stir as needed until the butter fully melts.
177 g whole milk, 28 g butter, 15 g honey
Remove the saucepan from the heat and then add the psyllium husks. Stir immediately and let sit for 5 minutes to form a gel.
14 g whole psyllium husks
While the psyllium gels, add the tapioca, millet, oat flour, and salt to a medium sized bowl. Whisk to combine and set aside.
109 g tapioca flour, 82 g millet flour, 82 g gluten-free oat flour, 7 g salt
Add the starter and egg to a large mixing bowl. Whisk to combine and then add the psyllium/milk gel and continue whisking until fully incorporated.
234 g gluten-free sourdough starter, 1 large egg
Add the dry ingredients to the wet ingredients and use a dough whisk to combine until you get a shaggy dough. Then switch to your hands to finish mixing until you get a dough ball with no dry flour left in the bowl.
Cover your kitchen scale with plastic wrap and then set the dough ball on it to weigh. Divide the weight by 12 to get the size each dinner roll should be. This should be around 63g if you want to skip this part.
Place the dough on your counter and cut it into 12 pieces, then weigh each one before shaping into a round ball. Place each dough ball in the prepared baking dish.
Cover the rolls and let them sit at room temperature for 3-5 hours until doubled in size. Alternatively, let them sit at room temperature for 1 hour and then place them in the fridge overnight. Let them finish proofing the next day before baking.
Preheat your oven to 400℉ about 30 minutes before you are ready to bake. Prepare an egg wash if desired by whisking 1 egg with 1/4 tsp salt.
Brush the rolls with the egg wash and then place them in the oven. Immediately turn the oven down to 350℉ and bake for 35 - 45 minutes until golden brown. Brush with melted butter while hot. Serve warm.