Classic Hong Kong Pineapple Buns with Butter (Bolo Bao)

To make the bun dough, combine 2 1/4 cups flour, granulated sugar, yeast, and salt in a large bowl. In a separate bowl, whisk together warm milk and half of the beaten egg. Add the wet ingredients to the dry ingredients and mix until a shaggy dough forms. Knead for 5 minutes, then add 2 tablespoons softened butter and continue kneading for 10-12 minutes until the dough is smooth and elastic. Place the dough in a lightly oiled bowl, cover, and let rise in a warm place for 60-90 minutes, or until doubled in size.

While the dough rises, prepare the pineapple topping. In a medium bowl, cream together 1/4 cup softened butter and powdered sugar until light and fluffy. Gradually mix in 1/2 cup flour and 1 tablespoon milk until a soft dough forms. Cover and refrigerate until ready to use.

Once the bun dough has doubled, gently punch it down and divide it into 8 equal pieces. Roll each piece into a smooth ball and place them on a parchment-lined baking sheet, leaving space between each bun. Cover loosely and let rise for another 30 minutes.

Preheat your oven to 350°F (175°C). Divide the chilled pineapple topping into 8 equal portions. Flatten each portion into a disc large enough to cover the top of a bun. Gently place a topping disc over each risen bun.

Using a knife, lightly score a crisscross pattern on the surface of each pineapple topping to resemble a pineapple. Be careful not to cut through to the bun dough. Brush the tops of the scored buns with the remaining beaten egg.

Bake the buns in the preheated oven at 350°F (175°C) for 15-18 minutes, or until golden brown on top and cooked through. The topping should be slightly crisp.

Remove the buns from the oven and let them cool slightly on a wire rack. Once warm, slice each bun horizontally and insert a thick slice of cold unsalted butter into the center. Serve immediately.