Hong Kong Style Pineapple Bun with Custard Filling

For the bun dough: Combine 2 cups all-purpose flour, 1/4 cup granulated sugar, and 1 teaspoon instant dry yeast in a large bowl. Add 1/2 cup warm milk and 1 large egg, mixing until a shaggy dough forms. Knead for 5 minutes, then incorporate 2 tablespoons softened unsalted butter and continue kneading for another 5-7 minutes until the dough is smooth and elastic. Cover and let rise in a warm place for 45 minutes, or until doubled in size.

For the pineapple topping: In a separate bowl, cream together 1/4 cup softened unsalted butter and 1/4 cup powdered sugar until light and fluffy. Beat in 1 large egg yolk, then gradually add 1/2 cup all-purpose flour, mixing until a soft dough forms. Set aside.

For the custard filling: In a small saucepan, whisk together 1/4 cup custard powder, 1/2 cup milk, and 2 tablespoons granulated sugar until smooth. Cook over medium heat, stirring constantly, for 3-5 minutes until the mixture thickens to a pudding-like consistency. Remove from heat, stir in 1 tablespoon unsalted butter, and let cool completely.

Once the bun dough has risen, punch it down gently and divide it into 8 equal portions. Roll each portion into a smooth ball. Flatten each bun dough ball slightly and place a spoonful of cooled custard filling in the center. Gather the edges of the dough to seal the filling inside, forming a round bun.

Divide the pineapple topping dough into 8 equal portions. Flatten each portion into a thin disc, large enough to cover the top of a bun. Gently place a topping disc over each filled bun, pressing lightly to adhere. Use a knife to score a crisscross pattern on the topping, resembling a pineapple.

Place the prepared buns on a baking sheet lined with parchment paper. Let them rest for 15 minutes while the oven preheats. Bake at 375°F (190°C) for 18-20 minutes, or until the buns are golden brown and the topping is crisp.

Remove from the oven and let cool slightly on a wire rack before serving.