Nutella Babka

Deliciously sweet and addictive bread swirled with Nutella and topped with buttery cinnamon crumbles! 
Ingredients
1 cup 2 Tablespoons 270ml whole milk divided
2 and 14 teaspoons active dry or instant yeast 1 standard size packet
12 cup 100g granulated sugar
12 cup 8 Tbsp 113g unsalted butter softened to room temperature and cut into 4 pieces
2 large eggs at room temperature and divided
12 teaspoon salt
4 and 14 cups 531g allpurpose flour spooned leveled plus more for dustingrolling
2 cups 600g Nutella divided

Crumble Topping
14 cup 50g packed light or dark brown sugar
14 cup 31g allpurpose flour
12 teaspoon ground cinnamon
14 cup 4 Tbsp 56g unsalted butter cold and cubed
Instructions
Make the dough Heat 1 cup of milk to about 95F 35C. You can use the microwave or stovetop. Pour the warm milk into the bowl of an electric stand mixer fitted with the dough hook attachment or you can use a handheld mixer or no mixer but a stand mixer is ideal. Manually whisk in the yeast and 2 teaspoons of the granulated sugar. Cover the bowl with a clean towel. The mixture should be frothy and foamy after 5 minutes.
On low speed beat in the remaining sugar and the softened butter until butter is slightly broken up. Next beat in 1 whole egg plus 1 egg yolk reserve the egg white and the salt. The butter wont really be mixing in so dont be alarmed if it stays in pieces. On low speed gradually add the flour. Once it is all added beat on medium speed until a soft dough forms about 1 minute.
Knead the dough Keep the dough in the mixer and beat for an additional 68 full minutes or knead by hand on a lightly floured surface for 68 full minutes. If youre new to breadbaking my How to Knead Dough video tutorial can help here. If the dough becomes too sticky during the kneading process sprinkle 1 teaspoon of flour at a time on the dough or on the work surfacein the bowl to make a soft slightly tacky dough. Do not add more flour than you need because you do not want a dry dough. After kneading the dough should still feel a little soft. Poke it with your fingerif it slowly bounces back your dough is ready to rise. You can also do a windowpane test to see if your dough has been kneaded long enough tear off a small roughly golfballsize piece of dough and gently stretch it