Start by warming your milk until it’s just warm to the touch – about like bath water. Pour it into a large mixing bowl and sprinkle the yeast over top. Let it sit for about 5 minutes until it gets foamy – this tells you your yeast is alive and ready to work.
While the yeast is blooming, whisk together 3 cups of the flour (save that last ¼ cup for later), sugar, and salt in a separate bowl. Once the yeast mixture is foamy, add your eggs, softened butter, and vanilla.
Add the dry ingredients to your wet ingredients and mix until a shaggy dough forms. Now’s when the real work starts – knead the dough for about 8-10 minutes. At first, it’ll be sticky and messy, but keep going! You’ll feel it transform under your hands into a smooth, elastic dough that springs back when you poke it. If it’s still super sticky after 5 minutes of kneading, work in some of that reserved flour, a tablespoon at a time.
Place your dough in a lightly greased bowl, cover with plastic wrap or a damp towel, and let it rise in a warm spot until doubled in size – usually about 1½ hours. You’ll know it’s ready when you poke it with your finger and the indent stays.
Once risen, punch down the dough and roll it out on a floured surface into a large rectangle, about 18×12 inches. The dough should be about ¼ inch thick.
Mix your melted butter and Nutella until smooth. Spread this mixture evenly over your dough, leaving about a ½-inch border around the edges. Try to get it as even as possible.
Starting from the long edge, roll the dough up tightly into a log, like you’re making cinnamon rolls. Place the log seam-side down and cut it into 12 even pieces. I find it easiest to cut the log in half, then each half in half, then each piece into thirds.
Place each bun into a greased 9×13 inch baking pan, leaving some space between them for rising. Cover and let rise again for about 45 minutes, until they’re puffy and touching each other.
While they’re rising, preheat your oven to 350°F. Once the buns are ready, bake for 25-30 minutes. You’re looking for a deep golden brown color on top, and if you tap one, it should sound hollow.
While they’re baking, make your sugar syrup. Combine water and sugar in a small saucepan and bring to a boil, stirring until the sugar dissolves completely. Let it simmer for 2 minutes until it’s slightly thickened.
As soon as the buns come out of the oven, brush them generously with the warm sugar syrup.