First, prepare the starter. In a medium bowl, combine the flour, water, and yeast and mix until all the flour has been absorbed. Cover with plastic wrap and let sit at room temperature overnight or up to 16 hours.

Once the starter is ready, make the dough. In the bowl of a stand mixer fitted with the dough hook, combine the starter with the yeast, milk, orange juice, dry milk, potato flour, melted butter, salt, sugar, and about 2 cups of the whole wheat flour

Knead until a dough forms, then add more of the flour as needed for dough to not be sticky and easily come off the sides of the bowl. Knead 6-7 minutes on low speed {you can also do this by hand!}

After kneading, transfer dough to a lightly greased bowl, cover, and allow to rise until it becomes puffy and 1.5x in size {about 90 min}. Note that it will not rise as high or as fast as white flour.

When ready to make the dough, lightly flour your work surface, and roll the dough out to about 9" x 16". Spread Nutella all over the surface, then tightly roll up the long side {you want it to be 9" wide to fit in the pan}.

You can put the bread in the pan as-is, OR to get the braided swirl effect, take a sharp knife and cut the rolled bread loaf in half length-wise. Rotate the dough so that the cut lines of Nutella face up, then gently overlap the two pieces to make a "braid."

Lightly grease a 9x5 loaf pan, and put a piece of parchment inside to facilitate removal later. Carefully set the bread in the pan, and allow to rise one last time until the dough crowns over the edge of the pan by ¾"... remember it will rise more as it bakes, too!

Preheat oven to 350F, and bake the bread for 10 minutes uncovered, then cover with a piece of foil and bake for 45-50 minutes longer, until the center registers 190F with a thermometer.

Let cool slightly before handling, then remove bread from pan and brush the surface with more unsalted butter. Enjoy!