Heat milk, water and butter in microwave until butter is mostly melted (do not boil). Meanwhile, combine 3/4 cup of brown rice flour with xanthan gum, sugar, yeast and salt.
Pour warm liquid into flour mixture. Beat on medium speed 2 minutes with a hand mixer.
Add 1/4 cup flour and egg and beat on high 2 minutes. Stir in enough additional flour (1/2 to 1 cup) to make a sticky dough (sticky cookie dough).
Cover & let rise in a warm place 15 minutes or doubled in size. Use a large cookie scoop to drop rolls on a greased cookie sheet. Allow to double in size. For hamburger buns, use a little more dough and flatten slightly with the palm of your hand. Bake 350* 10-12 minutes until golden brown. Brush with butter while hot. Makes 8 dinner rolls or 3 full hamburger buns (6 hamburger bun halves).