Using a stand mixer or wooden spoon, mix and knead all of the dough ingredients — flour through butter — until it comes together into a soft, smooth ball. The dough should be pliable, not very sticky, and bounce back when poked lightly with your finger.

Place the dough in a lightly greased bowl and set aside on the counter. Allow it to rise for 60-90 minutes, until nearly doubled in size. Meanwhile, lightly grease a 9-inch round pan and set aside. (I love using a springform pan for this, but a cake pan also works well.)

Turn the dough out onto a lightly floured work surface. Pull off about a quarter of it — you'll use this to form the braids. Shape the remaining large piece of dough into a smooth ball, and place in the center of the prepared pan.

Divide the reserved piece of dough into three equal pieces, and roll each one out into a strand about 18"-20". Use these three strands to create one long braid. (See photos in post for a visual.)

Cut the braid in half, then place in a cross on top of the larger piece of dough in the pan. (Alternatively, you could wrap the braid in one length around the inside edge of the pan.)

Cover the loaf and let rise for about 45 minutes, until approximately doubled in size. Near the end of the rising time, preheat the oven to 350 degrees F (180 C) and place a rack in the lower-middle.

When the bread has risen, make the topping. Beat the egg and water together with a fork in a small bowl, and brush the mixture gently over the loaf. Sprinkle with additional sugar, as desired.

Bake bread for 35 to 45 minutes, until the top is a rich golden brown. Remove from the oven and let cool completely before cutting and serving.