Make the Dough: Combine flour(s), yeast, sugar,salt, dry milk, potato flour, butter and lukewarm water in a large bowl or the bowl of a stand mixer. Mix and knead to make a soft, smooth dough.
Place the dough in a lightly greased bowl, cover and let it rise for 60 minutes, until it's nearly doubled in volume.
Divide the dough into 4 equal pieces. Shape each piece into a ball. Cover them and let them rise for 15 minutes.
On a lightly greased or floured surface, roll 1 piece of dough into 10" circle. Place the circle on a parchment lined baking sheet. Spread nutella evenly on the surface, leaving 1/4" of bare dough around the perimeter. Roll out a second dough circle the same size as the first and place it on top of the first, Nutella covered circle. Repeat the layering process - Nutella, dough circle -- leave the top circle bare.
Place a 2½"~3" round cutter or a bowl or a glass in the center of the dough circle as a guide. With a sharp knife, cut the circle into 16 equal strips, from the cutter to the edge, through all the layers. Using 2 hands, pick up two adjacent strips and twist them away from each other twice so that the top side is facing up again. Repeat with the remaining strips of dough so that there are eight pairs of strips. Pinch the pairs of strips together to create a star-like shape with eight points.
Cover the star and let it rise until it becomes noticeably puffy, about 45 minutes.
Preheat the oven for 400°F.
Brush the star with almond milk and bake for 12~15 minutes, until it's nicely golden.
Remove from the oven and allow to cool for about 10 minutes before serving.