Preheat oven to 450 degrees Fahrenheit.In a large bowl, sift together flour, salt, baking powder, and xanthan gum. Cut in butter until mixture has pea-sized flour-coated butter pieces throughout.Make a well in the center of the mixture. Add the milk and cheese to the well and stir to combine.Drop batter by spoonfuls onto a greased baking sheet or a baking sheet lined with parchment paper. (Note: The original recipe called for ungreased baking sheets, but the biscuits stuck to the pan a little.)Bake in preheated oven for 12 to 15 minutes until lightly browned. Keep an eye on them though. Mine were cooking pretty quickly. I actually turned the oven down to 350 degrees the last couple of minutes, but that change could be just necessary for my "fast" oven.While biscuits are baking, melt butter and mix with minced garlic. Spoon in equal portions onto the biscuits.Makes about 16 biscuits (about 2 inches in diameter).