05Stir in additional flour, 1/4 cup at a time, first with the spoon and then by hand, or with the beater and then the dough hook.
06The dough will form a rough mass and clean the sides of the bowl.
07Because of the large amount of butter, the dough will not be sticky. It should be firm, but not stiff.
08Turn the dough out onto a floured work surface. With a strong push turn fold action, knead till the dough is smooth and elastic, about 8 minutes, or knead with the mixer under the dough hook for the same length of time.
09Return the dough to the bowl; cover with plastic wrap and put aside at room temperature till the dough has doubled in volume, about 1 hour.
10Punch down the dough and turn it onto a floured surface; knead briefly to work out air bubbles.
11Divide the dough into 3 equal parts. Roll each part under your palms into a strand 14 inches long.
12Beginning in the middle of the strands, braid loosely to one end. Reverse the loaf and again braid from middle to end.
13Pinch the ends closed and place on a baking sheet.
14Cover the dough with wax paper and leave till doubled in bulk and puffy to the touch, about 1 hour.
15Preheat oven to 350°F 20 minutes before baking.
16Before baking, brush the braid with the egg white glaze.
17Bake till the crust is rich brown, about 45 minutes.
18A wooden toothpick inserted in the center should come out clean.
19Remove braid from the oven. Use a metal spatula to lift it off the baking sheet, because the hot loaf will be fragile and might break.
20Cool on a wire rack.
21This bread keeps well and toasts beautifully and also freezes well.