• In the bowl of an electric mixer fitted with a paddle attachment on medium-low, mix together 1 cup flour, active dry yeast, ¼ cup granulated sugar, and 1½ teaspoons salt, before adding ½ cup warm water. 
• Now add in 1 egg at a time. Only add the next egg when the previous egg is well incorporated.
• Set the mixer to low. Add in 2 cups of flour, a ¼ cup at a time, until the dough has come together.
• Add the softened cubes of butter in 6 separate batches, waiting until the butter is well incorporated after each batch before adding more.
• Set mixer to low. Now add in 1¾ cups of flour, a ¼ cup at a time until the dough is well-combined. This dough will be very sticky, but not gooey, when it’s done.
• Use a rubber spatula to clean the dough off the mixing paddle, and scrape the sides of the mixing bowl. Cover the dough with a plate or plastic wrap and let it proof at room temperature for 3 hours, until it doubles in size.
• After 3 hours, punch down the dough with a rubber spatula. Cover the dough with plastic wrap, and refrigerate it overnight (6-12 hours) until 3 hours before you’re ready to bake the next day.

Next Day

• Remove the dough from the refrigerator a couple hours before you're ready to shape. Divide it into two equal pieces. Shape them into loaves (or braid them by slicing the half of dough into three long strips to braid) on a clean, lightly floured surface, and place each into its own loaf pan. Whatever you do, the dough should fit snugly in the loaf pan.
• Cover each loaf pan with clear plastic wrap, and let rise at room temperature for about 3 hours, until doubled in size. Once risen, mix together egg wash ingredients and gently brush on the dough using a pastry brush.
• Preheat the oven to 350 degrees F (180 degrees C). Remove the plastic wrap and bake for 38-40 minutes in the center of the oven. Remove from oven and let the bread sit in the pan for 5 minutes to cool before transferring the loaves from the pans to a cooling rack. Let cool completely so the bread does not fall apart.
• Once the bread has cooled completely, store in an air tight container or large zip top container for up to 3-4 days.