Make the tangzhong: Whisk together the flour and milk in a microwave safe bowl. Microwave for 30-second increments, about 3 to 4 times stirring in between bursts. Let the mixture cool completely before incorporating it with your other ingredients or the heat may kill the yeast in your starter.
150 grams milk, 40 grams all-purpose flour
Make the dough: Combine the cooled tangzhong with the all-purpose flour, milk, egg, sugar, salt and sourdough starter. Mix until the dough comes together.
300 grams all-purpose flour, 113 grams milk, 1 egg, 60 grams cane sugar, 6 grams salt, 113 grams sourdough starter
Add the butter: Knead the butter into the dough one tablespoon at a time. Wait until each portion of butter is absorbed into the dough before continuing to add more. Cover the dough in plastic wrap and let the dough rest for 30 minutes.
70 grams unsalted butter
Strengthen the dough: Turn the dough out on a lightly floured work surface. Knead the dough until completely smooth, about 5 minutes.
Bulk fermentation: Let the dough proof until it looks airy and has doubled in volume.
Cold proof: Deflate the dough and round it into a tight ball. Place the dough in the refrigerator and proof overnight.
Make the filling: Melt the butter in a small saucepan over medium-high heat. Add the desiccated coconut to the pan and toss until fully coated. Whisk the sugar and cornstarch together in a small bowl and add it into the saucepan with the milk. Cook mixture until the milk is completely absorbed, about 30 minutes. Transfer the mixture to a bowl and allow it to cool completely.
42 grams unsalted butter, 100 grams desiccated coconut, 100 grams cane sugar, 15 grams cornstarch, 169 grams milk
Shape: Line a baking sheet with parchment paper. Turn the dough out on a lightly floured surface. Using a bench scraper, divide the dough into 12 portions, round each portion into a tight ball. Cover the dough balls with plastic wrap, let the dough rest for 15 minutes, this makes the dough easier to work with.
Working with one portion of dough at a time. Flatten the dough out into a disc using a rolling pin. Place one tablespoon of filling in the middle of the dough. Fold the edges of the dough towards the center. Pinch the seam shut and place the shaped dough on the prepared baking sheet.
Repeat with the remaining dough portions. Position the shaped dough on the baking sheet with room to spread, about 2 inches apart. Using a fork, make an "X" in the center of each roll.
Second proof: Cover the baking sheet with plastic wrap and set it in a warm place. Let the dough rise for 1 to 2 hours or until the dough looks puffy and well-risen.
Prep: When the dough is almost ready, preheat the oven to 350 F. Beat the egg for the egg wash. Remove plastic wrap and brush the dough with egg wash.
1 egg
Bake: Bake for 20 to 30 minutes or until golden brown. Transfer the rolls to a wire rack until cooled.
Enjoy: These rolls are best enjoyed fresh from the oven the same day they are baked.
Store and reheat: Store bread in a zip lock bag at room temperature for up to 3 days. To reheat, heat the rolls on a baking sheet tightly covered in foil for 10 to 15 minutes or until completely warmed and soft.