Ingredients
For the Dough
- 3/4 cup whole milk, warm
- 2 tsp instant yeast
- 1 large egg
- 1/2 cup water
- 2 tbsp granulated sugar
- 4 cups bread flour
- 1 tsp kosher salt
- 3 tbsp salted butter, softened
For the Filling & Coating
- 1 1/2 cups (3 sticks) salted butter, cold
- 3 tbsp toasted white sesame seeds
- 2/3 cup untoasted white sesame seeds
- 1/4 cup black sesame seeds
- 1 large egg
- 1 tbsp milk
Make and Proof the Dough
In the bowl of a stand mixer, combine the warm milk and instant yeast. Let it sit for ~5 minutes until foamy. Add the egg, water, and granulated sugar, and whisk to combine.
Add the bread flour and kosher salt. Knead with the dough hook on low speed for ~5 minutes until a shaggy dough forms. Add the softened salted butter and continue to knead on medium speed for another ~6-8 minutes, until the dough is smooth and elastic.
Shape the dough into a ball, place it in a lightly oiled bowl, and cover. Let it proof in a warm spot for about an hour, or until doubled in size.
While the dough proofs, cut the cold butter for the filling into 12 rectangular logs, about 3 inches long and 1/2-inch thick. Arrange them on a plate and place them in the freezer until you're ready to shape the buns.
Shape the Buns
Once the dough has proofed, turn it out onto a clean surface and divide it into 12 equal pieces.
Working one piece at a time, shape the dough into a teardrop about 6 inches long. Use a rolling pin to flatten it into a long triangle.
Place one log of frozen butter at the wide end of the dough and sprinkle with some of the toasted sesame seeds. Roll the dough over the butter, pinching the ends to seal it in. Continue rolling the dough up toward the pointed end.
Place the shaped buns on a parchment-lined baking sheet, leaving a few inches of space between them. Cover and let them proof for another 90 minutes, until they have doubled in size.
Coat and Bake
When you're ready to bake, preheat your oven to 375F.
In a small bowl, whisk together the egg and milk for the egg wash. In a separate, shallow bowl, combine the untoasted white and black sesame seeds.
Gently brush one of the proofed buns with the egg wash. Immediately place it in the bowl of sesame seeds and turn to coat all sides.
Return the coated bun to the baking sheet. Repeat with the remaining buns.
Bake for ~18-20 minutes, until the buns are deep golden brown. Let them cool on a wire rack for a few minutes before serving.
