Combine first 3 ingredients in a large mixing bowl and whisk. Add flour and stir with a strong spoon or hand until no dry spots remain. Cover and rest for 30 minutes. (This resting period will dramatically reduce the time needed to knead the butter-laden dough to adequate strength. Most brioche recipes with high butter % require that you run your mixer in excess of 20 minutes. That is a surefire way to burn up a good home mixer that we are avoiding.) Uncover dough, and with dough hook on mixer, slowly incorporate sugar and salt, 1-2 minutes. Take cubed butter directly from the fridge, turn mixer speed to medium, and while mixing add in chunks of butter every 30 seconds or so, 3-4 minutes. Turn mixer to med-high and allow to knead 8-10 minutes. If you find butter has crept up the sides of the bowl, turn off mixer, scrape down, and continue. The chunks of cold butter will eventually break up and combine with the dough to form a homogeneous whole, but not before looking like the floor of a neglected guinea pig cage. If you don’t already take a folded kitchen towel and place it under you mixer I think today is the day you start. It keeps things quiet and clean. And take heart; the mess of dough and butter will soon combine into a smooth, satiny dough that slaps against the side of the bowl and stretches and pulls with the dough hook. Remove dough from mixer bowl and form into a simple round by folding it over itself and making small quarter turns as you go. Triple wrap dough in buttered cellophane and refrigerate overnight and up to 4 days before you plan to bake. This is a great recipe for those who like to prepare days in advance of their spring luncheons.

Butter and flour two 8 x 4 inch loaf pans. If you're feeling saucy you can also bake this in a bundt pan and fill the baked brioche center with molten chocolate just before serving. Heads will roll. Jaws will drop. Remove dough from fridge, unwrap, and on a lightly floured board cut your very cold dough in half. Each half of dough should be cut into eighths, making 16 total pieces. Gently flatten each piece with the floured palm of your hand, fold the edges over themselves, and form into a little ball of dough. With the seam side down, place the ball of dough in a loaf pan. When finished, each pan will have two rows of four dough balls. Brush the whisked egg over loaves and leave, covered, at room temperature, 1½ to 2 hours, or until they have risen just over half the sides of the pan. Bake loaves at 375 degrees Fahrenheit for 30-40 minutes, until golden amber and shiny. Cool fully. Serve it forth.