2 1/2 cups (350 g) all purpose gluten free flour (I used Better Batter)
1 1/4 teaspoons xanthan gum (omit if your blend already contains it)
1/4 teaspoon cream of tartar
1 1/2 teaspoons kosher salt
5 tablespoons (40g) powdered milk or buttermilk
1 teaspoon baking powder
1/4 teaspoon baking soda
3 tablespoons (41 g) packed light brown sugar
2 teaspoons apple cider vinegar
2 egg whites (50 g), at room temperature
4 tablespoons (56 g) unsalted butter, at room temperature
6 fluid ounces gluten-free beer of choice
4 to 5 tablespoons fresh oregano leaves, minced
1 extra tablespoon unsalted butter (optional)
Preheat your oven to 375°F. Grease well a nonstick loaf pan that is no more than 9 inches by 5 inches, and set it aside.
In a large bowl, place the flour, xanthan gum, cream of tartar, salt, whey powder, baking powder, baking soda and brown sugar. Whisk to combine well. Add the cider vinegar, egg whites, butter and the beer, and mix to combine. The dough will be shaggy and soft. Add the minced oregano, and mix to distribute the oregano evenly throughout the dough.
Scrape the dough into the prepared loaf pan. With very wet fingers or a wet spatula, spread the dough evenly in the pan and smooth the top. Tent the loaf pan with a piece of aluminum foil, making sure you leave room for the bread to rise without touching the foil.
Place the tented loaf pan in the center of the preheated oven and bake for 25 minutes. Slide the pan out of the oven, rotate the pan 180 degrees, and remove the foil. With a very sharp knife, make a shallow slice down the center of the bread lengthwise (without reaching either end). Rub the extra tablespoon of butter all over the top of the bread (it should melt completely into the hot bread). Return the uncovered bread to the oven and bake until the top is golden brown and a toothpick inserted into the center of the bread comes out clean (about another 20 minutes).
Remove the pan from the oven and allow the bread to cool in the loaf pan for at least 15 minutes. Transfer the loaf pan to a wire rack to cool completely before slicing and serving.