In the bowl of your stand mixer (or a mixing bowl if using a hand mixer), carefully measure out and add the flour, sugar, yeast, salt, and xanthan gum. Weighing ingredients with a gram scale will give the best results.
Using your stand mixer fitted with the flat beater attachment (or a hand mixer with beaters), gradually beat in the warm milk. Don’t worry if the mixture looks crumbly at first—it will start to come together once all the milk is added.
Add the softened butter and beat until fully incorporated. The mixture will begin to smooth out.
Beat in the eggs, one at a time, ensuring each egg is thoroughly blended before adding the next. Take your time here!
Once all the eggs are added, increase the mixer speed to HIGH and beat for exactly 3 minutes. This step is crucial, as it incorporates air into the thick batter to help replace the missing gluten. The finished batter should be smooth and silky, more like buttercream than traditional bread dough.
Cover the bowl with plastic wrap and set it in a warm place to rise for about 1 hour. The dough won’t double in size but should become slightly puffy.
After the rise, gently stir the dough to deflate the puffiness. Scrape the batter into a lightly greased 8 ½ x 4 ½ loaf pan using a rubber scraper.
Cover the pan loosely with plastic wrap and let the dough rise until it just reaches the rim of the pan (this may take around 30 minutes). Preheat your oven to 350°F towards the end of the rising time.
Bake the bread for 38-42 minutes until it’s golden brown. The internal temperature should reach about 205°F.
Remove the bread from the oven and turn it out onto a cooling rack. For a soft, flavorful crust, rub the top with a stick of butter while the bread is still warm. Allow the loaf to cool completely before slicing.