This super-soft, tender loaf gets its milk bread-like texture from low protein pastry flour. The semolina flour adds a gorgeous yellow hue and an ever-so-subtle crunch. The buttermilk is the background note bringing it all together, adding a touch of tanginess that makes this bread ideal for toast slathered with salted butter and suitable for sandwiches, too.
Weigh your flour; or measure it by gently spooning it into a cup, then sweeping off any excess. Combine all of the dough ingredients and mix, then knead — by hand, mixer or bread machine — to form a smooth, soft dough, adding additional water or flour as necessary, about 8 minutes.
Allow the dough to rise, covered, until almost doubled, about 1 1/2 hours.
Turn the dough out onto a greased surface, gently deflate it, and shape it into an 8 1/2" log.
Place the log in a lightly greased 9" x 5" pan, cover the pan, and allow the loaf to rise for 45 minutes, until it's just crowned over the top of the pan.
To make the topping, whisk egg white with water.
Brush the top of the loaf with lightly beaten egg white, and sprinkle with sesame seeds.
Bake the bread in a preheated 350°F oven for 35 to 40 minutes, until it's golden brown and its internal temperature registers 190°F or above on an instant-read thermometer.
Remove it from the oven, cool it in the pan for 10 minutes, then turn it out of the pan and cool completely for easiest slicing.
Store, wrapped, at room temperature for 4 days, or freeze for up to 3 months.
Use all King Arthur Unbleached All-Purpose Flour, if you choose, increasing the water to about 1 1/4 cups (306g).
