Scald the milk by heating it in a small pot over low heat just until small bubbles appear at the edges of the pot. Turn the heat off and let the scalded milk cool until just warm to touch.
¼ cup (60 milliliters) whole milk
In the bowl of your stand mixer, combine the flour, sugar, yeast and salt. Add the scalded milk and mix on low until all of the flour mixture has been moistened.
3½ cups (400 grams) unbleached all-purpose flour, 2 tablespoons granulated sugar, 1 packet (2¼ teaspoons or 7 grams) instant yeast, ½ teaspoon salt
In a small bowl, lightly beat three of the eggs, then add them all at once to the mixing bowl with the flour mixture and mix on low until the dough starts to come together.
4 large eggs
Turn the mixer up to medium to knead the brioche dough and start adding the butter cubes one at a time. It should take a few minutes for you to add all the butter and it to get incorporated into the dough.
16 tablespoons (227 grams) unsalted butter
Use the mixer to knead the brioche dough until it is smooth and elastic. Try to resist the urge to add any more flour, but you might need to scrape the bowl to get to release from the bottom of your mixing bowl. It will be sticky at this point.
Add the chocolate chips and knead using the mixer or by hand until fully incorporated.
1 cup bittersweet chocolate chips
Shape the brioche dough into a ball and let it rise in a greased mixing bowl covered with plastic wrap until doubled in size. This will take 1½ to 2 hours.
Punch down the brioche dough, then shape it into a loaf. Place the brioche loaf into a greased 9 by 5 inch loaf pan and cover it with plastic wrap. Let the brioche dough rise again until it sits about an inch above the pan lip, about 1 hour.
About 30 minutes before you are ready to bake your chocolate chip brioche, heat your oven to 400 degrees Fahrenheit. Beat the final egg in a small bowl, and brush the risen brioche loaf with egg wash, being careful not to get the egg on the edges of the loaf pan.
Bake for 10 minutes at 400℉, then reduce the oven temperature to 350℉ and continue baking until the internal temperature of the brioche is 190 to 195℉, about another 40 minutes. If the top is browning too quickly, tent the loaf with foil.
Remove the chocolate chip brioche immediately from the pan, and let it cool at least an hour before slicing.