In a large bowl, combine all-purpose flour, salt, sugar, yeast and milk, mixing until dough is partially formed.
If you're using cups instead of weights: instead of adding the total amount of flour asked, add only 4 cups. Only add the remaining ¼ cup if the dough feels too sticky.
Add room temperature butter, and using a stand mixer (on medium speed, dough hook), knead dough for 5 minutes. You can use your hands to knead the dough. If doing so, knead for 8 to 10 minutes. Dough should feel soft and just a bit tacky.
Place dough into a clean bowl, covering it with a plastic wrap or damp towel.
Let dough rise for 1h30 in a warm spot. It should double in size.
Line a 9x9 inch baking pan with parchment paper.
In a lightly floured surface, roll the dough open in a rectangular shape, about ¼ inch thick. If using premade dough, spread it open in a clean surface.
Spread Nutella, cinnamon, brown sugar and chocolate chips/chunks evenly through all the dough but a margin of about 1 inch along the long side. Leaving that space with no spreading helps to seal the dough after rolling.
Roll the dough closed, pinching the edges to seal it shut. As you roll the dough, stretch it towards you and over so it stays tight and not floppy.
Cut the dough into 1 ½ inches rolls and place each roll into prepared baking pan. Leave enough space between each one to allow them to grow properly - ¼ inch is more than enough.
Cover with a damp towel or plastic wrap and let them rise for 45 minutes. They will look light and puffy when ready to bake.
Preheat the oven to 350°F.
Bake the rolls for 25 minutes, or until they’re lightly golden at the top.
For the chocolate glaze, start by mixing melting the butter and cocoa powder until combined.
Add icing sugar, hot water and vanilla extract, and mix until all ingredients are full combined. Glaze should be smooth, with no hard lumps.
Spread chocolate glaze over warm chocolate rolls with the help of a spatula or spoon.