In a small dish, combine the yeast with 1 teaspoon of sugar.
Add the warm milk and stir.
Set aside for about 5 minutes.
Meanwhile, in a large mixing bowl (of electric stand mixer) whisk the eggs, at medium speed for about 2 minutes.
Add the sugar and continue to whisk for another 2 minutes or so.
Switch to paddle attachment; add the butter, shortening, salt and vanilla extract.
Mix on medium speed until well combined.
Add the yeast mixture and mix until well combined.
Add 2 cups of flour and combine.
Switch to hook attachment.
Gradually add the 4 cups of flour and knead for about 5-8 minutes or until the dough pulls away from the sides of the bowl of the stand mixture. Dough will be soft.
Divide dough into 18 balls of dough (each weighing about 90 grams).
Place the dough balls in an airtight container, and refrigerate overnight (or up to 24 hours).
Preheat oven to 350° F.
Line baking sheet with parchment paper.
Working with one ball of dough at a time, roll out the dough to an 8 inch round, about 1/8 of an inch thick (I will usually do this between two pieces of parchment paper).
With a pastry cutter, cut dough into eights (first cut dough in half, then in quarters and then in eighths).
Place about ¾ teaspoon of Nutella® at the wide ends and begin to roll each section into a crescent shape.
Place on a parchment lined baking sheet.
Repeat with another ball of dough.
Brush tops of cookies with egg wash.
Sprinkle with sugar.
Bake for 10-12 minutes or until bottoms are lightly browned.
Transfer cookies to wire rack to cool.
There is an idle time of at least 12 hours.1 serving = 1 cookiePlease keep in mind that the nutritional information provided below is just a rough estimate and variations can occur depending on the specific ingredients used.