5 cups all purpose flour
1/3 cup sugar
1 teaspoon salt
2 tablespoons powder milk
1 teaspoon vanilla
2 large eggs
1 1/2 cups lukewarm milk
1 tablespoon plus 1 teaspoon yeast
6 tablespoons unsalted butter (room temperature)
Filling and topping
1 1/2 cups nutella
1 cup sweetened condensed milk
20grams dark chocolate (I use lindt 85% cocoa)
1/2 cup toasted chopped hazelnuts
Sift your flour, sugar,dry milk, and salt in a large bowl. Set aside. Set a small saucepan over low heat and add your milk, heat just until lukewarm. Place the yeast in a small bowl with 3 tablespoons of milk and a pinch of salt and allow it to bloom for 5to 10 minutes. In a stand mixer bowl add your butter and eggs and beat with a hand whisk until combined. Add 1 1/2 cups of milk and beat for approximately 3 minutes using your dough hook attachment under medium high speed. Add your milk and yeast and continue to mix until well combined. Slowly add the remainder of your flour mix and mix until a dough has been formed. Transfer dough to a lightly oiled or floured bowl and cover with plastic wrap or a damp kitchen towel. Set aside to rise in a warm, draft free place until doubled in size, 1 to 1 1/2 hours.
How to assemble the rolls
Butter a 9 by 13-inch glass baking dish. Turn the dough out onto a lightly floured work surface. Gently shape the dough into a rectangle with the long side nearest you. Roll into an 18 by 12-inch rectangle. Spread the dough with nutella (room temperature) leaving a 1/2-inch border along the top edge. Beginning with the long edge nearest you, roll the dough into a tight cylinder. Firmly pinch the seam to seal and roll the cylinder seam side down. Very gently squeeze the cylinder to create even thickness. Using a serrated knife, slice the cylinder into 1 1/2-inch to 2 inch rolls; yielding 12 rolls. Arrange the rolls cut side down in the baking dish and cover with a towel until doubled in size. Preheat your oven to 360 degrees F., place the rolls on the middle rack and bake until golden brown, approximately 20 to 25 minutes.
In a heavy sauce pan over low heat melt the chocolate with 2/3 of your sweetened condensed milk until the chocolate is melted. Mix to combine into and even color. Drizzle over warm buns and sprinkle with hazelnuts. Drizzle the remainder of your plain condensed milk over the buns. Serve warm.