PINEAPPLE BUNS

Steps:

• Make the tangzhong: In a small saucepan over low heat, combine the flour and milk and cook, whisking constantly, until thickened to a paste, 2 to 3 minutes. Immediately transfer the paste into a small bowl, scraping the sides of the saucepan with a flexible spatula; let cool until warm, 5 to 10 minutes. Texture should resemble mashed potatoes.
• Make the milk bread: In a clean or new small saucepan, scald the milk over medium heat, bringing the milk to a gentle simmer (watch carefully as milk tends to boil over). Pour milk into a small bowl and cool until warm to the touch (about 110°F). Stir in yeast and a pinch of sugar, and set aside until the surface of the mixture is foamy, 5 to 10 minutes.
• In the bowl of an electric mixer fitted with a dough hook, combine the sugar, flour, salt, and egg. Add the tangzhong and milk and mix on low until shaggy. Add the softened butter one piece at a time, mixing until fully incorporated before adding the next. Increase the speed to medium-high and continue to knead the dough until it is tacky and slightly sticky, 8 to 9 minutes. Transfer the dough to a lightly floured work surface. Wet your hands to prevent the dough from sticking, pinch and pull the ends of the dough to form a smooth ball.
• Coat a large mixing bowl with 1 teaspoon of oil. Add the dough to the bowl, gently turning it to cover with oil. Cover the bowl with plastic wrap and set in a warm spot to proof until doubled in size, about 2 hours (or place in the refrigerator to proof for at least 8 hours or overnight).
• While the dough is proofing, line two large rimmed baking sheets with parchment paper.
• Make the buns: After the first proof, punch down to deflate the dough and transfer it to a lightly floured surface. Pinch and pull the ends of the dough to form a smooth ball. Divide the dough into 12 equal portions with a bench scraper (for accuracy, weigh with a digital scale if you have one). Form each portion of dough into a smooth ball by pulling the ends of the dough underneath and then rolling between the palms of your hand, and arrange on the prepared sheets, spacing at least 3 inches apart. Cover with a damp, clean kitchen towel and set aside in a warm spot until the buns are doubled in size, 45 minutes to 1 hour.
• Meanwhile, make the topping: In a small bowl, whisk together flour, baking soda, and salt. In a medium bowl, combine the softened butter and sugar with a flexible spatula until smooth. Add the egg, vanilla, and food coloring, mixing until smooth. Fold the flour mixture into the butter mixture to form a sandy dough, then knead by hand until smooth. Pat into a disc and divide the dough into 12 equal portions with a bench scraper (for accuracy, weigh with a digital scale if you have one). Roll one piece into a smooth ball, then flatten into a 4-inch round with a dowel rolling pin. Score a crosshatch pattern into the dough with the edge of a bench scraper or knife, being careful not to cut all the way through. Use the edge of the bench scraper to lift the topping off the work surface. Repeat with remaining topping dough, setting each round aside until ready to top the buns. (Alternatively, you can skip making the crosshatch pattern. The topping will still crack beautifully as it bakes, just not as neatly.)
• Preheat the oven to 350°F. Brush the tops of the buns lightly with the egg white to help the topping adhere. Place one topping dough round on each bun, gently pressing to cover the entire outer edge (you want the dough to fully encase the top of the bun, if possible). Whisk the egg yolk in a small bowl and lightly brush over the topping of each bun.
• Bake the buns until golden brown, 18 to 20 minutes. Transfer the sheets to a wire rack. Let the buns cool for 5 minutes on sheets, then transfer to the rack to cool. Serve warm or at room temperature.