Spray your 8x4 or 9x5 bread loaf pan lightly with oil.
In your Kitchenaid mixer fitted with the paddle attachment add the 460 g. GF Flour, 8 g. Xanthan Gum, 10 g. Yeast, 1 g. Cream of Tartar, 27 g. Sugar, 13 g. Salt, and mix to combine.
Once the dry ingredients are combined add the 334 g. warm milk and 57. grams of softened butter, and 5 g. apple cider vinegar, mix until the dough comes together.
Next add the room temperature eggs one at a time, mixing each until they're fully incorporated.
Scoop the bread batter into the prepared bread loaf pan. Use a wet rubber spatula to smooth the top of the bread. You can keep dipping it in a cup of water while smoothing it to make the process go faster and keep the spatula from sticking. Once the top is smooth, cover it with plastic wrap and let it rise for 60 minutes. It won't double in size like normal bread dough, but it will get bigger and spongier.
Towards the end of the 60-minute rise, preheat the oven to 375°. Once the bread has risen, place it in the oven on the middle rack and bake for 45-60 minutes. It will be a nice golden brown color when it's ready to come out!
When the bread is finished baking, remove it from the oven and let it cool in its pan for 10 minutes. Then flip it out onto a cooling rack and let it finish cooling fully before slicing. Once cool, slice and enjoy!