How to Make It
For the challah, in a small bowl, sprinkle the yeast into the warm water. Set aside to bloom.
In a stand mixer fitted with a paddle attachment, combine the flour, sugar, butter, and salt, mixing on medium speed. Continue to beat until the butter has been distributed throughout the flour.
In a liquid measuring cup, whisk together the honey, eggs, egg yolks, oil, and water. Turn the mixer speed to low and add the liquid ingredients to the dry ingredients. Add the yeast with its water and continue beating until well combined.
Stop the mixer and change the paddle attachment to a dough hook.
Turn the mixer speed to high and let the dough hook knead the dough for at least 5 minutes, until it is shiny, smooth, and elastic.
Place the dough in a lightly oiled bowl and cover loosely with plastic wrap. Place the bowl in a warm, draft-free spot and allow the dough to rise until it has doubled in size, about 90 minutes.
Meanwhile, prepare the apple stuffing. In a medium bowl, combine the chopped apple, brown sugar, honey and cinnamon. Use a wooden spoon to stir and coat all the apples. Set aside.
Once the dough has fully risen, remove the plastic wrap and punch down the dough to release the air produced by the yeast. Turn the dough out onto a lightly floured work surface and allow it to rest for about 10 minutes.
Use a knife to divide the dough into three equal pieces. Use your rolling pin to roll each piece into a rectangle approximately 14 inches long and 6 inches wide. Place one-third of the apple filling down the center of a piece of dough. Pull one side of the dough over the filling and pinch to seal it closed on the other side and at the top and bottom. This will create a filled log of dough. Repeat with the other two pieces of dough.
Lay one of the logs vertically along the center of the prepared cookie sheet. Lay a second log across the middle of it, with the ends of the log pointing at 10 o’clock and 4 o’clock. Then lay the third log across the middle on top, with the ends pointing at 2 o’clock and 8 o’clock. Braid one side of the loaf from the middle down and then tuck the ends under. Turn the cookie sheet and repeat with the other side.
In a small bowl, combine the egg and water and use your pastry brush to generously coat the top and sides of the loaf with the egg wash. Sprinkle with the sanding sugar.
Cover the loaf loosely with a sheet of plastic wrap and set in a warm, draft-free place to rise again until it has nearly doubled in size, about 90 minutes.
Preheat the oven to 350°F.
Bake the loaf for 30 to 40 minutes, or until it is a lovely golden brown and a wooden skewer inserted in the center comes out clean.
Remove from the oven and allow the loaf to cool for at least 20 minutes on the cookie sheet before transferring to a cutting board and slicing.