Make the tangzhong

• Whisk the milk and flour in a small saucepan over medium-low heat until it thickens into a paste.
• Remove from the heat and let cool slightly.

Activate the yeast

• In a bowl, combine the warm milk, yeast and honey.
• Let sit until foamy.

Mix the dough

• In a large bowl, mix the bread flour, milk powder, sugar and salt.
• Add the yeast mixture, tangzhong, egg, egg yolk and vanilla.
• Mix until a shaggy dough forms.

Rest the dough

• Let the dough rest.

Knead in the butter

• Gradually knead the softened butter into the dough a little at a time.
• Continue kneading until the dough is soft, stretchy and slightly tacky.
• If kneading by hand and the dough becomes too hard, add a bit more flour until you can knead it into a smooth ball.

First rise

• Cover the dough and let it rise in a warm place until doubled.

Shape the buns

• Divide the dough into equal portions.
• Flatten each piece, place a scoop of Nutella in the center and fold halfway.
• Pinch the seams tightly closed and cut strips into the remaining half, then lay each strip over the top.

Second rise

• Place the buns into a parchment-lined baking dish, cover and let rise until puffy.

Bake

• Brush the buns with the egg wash.
• Bake at 350°F until deeply golden on top.
• Brush with melted butter immediately after baking so they stay soft.