In a small bowl, whisk the egg white with 1 tablespoon water, cover and refrigerate until ready to use.

In a 1 cup measuring cup mix the boiling water and the butter pieces until the butter is melted.

Add the room temperature water, plus the two whole eggs and egg yolk. Whisk to combine; set aside.

In the bowl of a stand mixer fitted with a dough hook, combine 3 cups of the flour, sugar, yeast, and salt.

With the mixer on low, slowly add the butter mixture and mix until the dough comes together.

Increase mixer speed to medium low and continue kneading for five to eight minutes, or until you have a cohesive, slightly tacky dough that just sticks to the sides of the bowl (if necessary, add up to an extra half cup of flour, one tablespoon at a time, until the desired consistency is reached).

Transfer the dough to a very lightly oiled bowl, cover and allow to rise until about doubled (1 to 1 1/2 hours). Once doubled, lightly press the dough down to deflate slightly, cover and allow to rise again until doubled (another hour or so).

After the second rise, transfer the dough to a lightly floured surface. Divide the dough into two pieces, one smaller than the other. The large piece will be 2/3 of the dough, while the small piece will be 1/3.

Divide each piece of the dough into 3 equal pieces. Set aside the smaller pieces for now. With the larger pieces, roll each piece into a 1-inch rope about 16-inches long. Pinch the top end of the 3 ropes together, then braid normally. To braid the dough, begin by lifting the right piece up and laying it over the middle piece, making the right piece become the middle piece. Now lift the left piece up and lay it over the new middle piece, making the left piece become the middle piece now.

Repeat until the dough is completely braided. Pinch the ends together, then gently roll them under the end and tuck them in. Repeat this process with the smaller pieces of dough to create another braid that is the same length.

Gently transfer the large braid onto a baking sheet lined with a Silpat mat or parchment paper, or very lightly greased. Brush a small amount of the egg wash over the top. Gently lay the smaller braid on top of the large braid, centering it as best as you can.

Cover the bread with a clean, dry towel and allow to rise until the dough is puffy and slightly lighter in color (about 45 minutes).

Heat the oven to 375°F. Brush the bread with the remaining egg wash. Bake for 30 to 35 minutes, until dark golden brown and the interior temperature reaches 190°F. Transfer to a wire cooling rack and allow to cool completely before serving.