Pineapple bun with butter (Bo lo bao)

Instructions

1. To make the bun dough, combine the sugar, yeast and 150 ml tepid water in a bowl. Set aside for 5 minutes or until the mixture starts to bubble. Stir in the egg, evaporated milk and lard, then add the flour and gently mix until well combined.
2. Turn out the dough onto a clean surface and knead for 10 minutes. Cover with a clean damp cloth and rest for 10 minutes. Knead the dough for another 10 minutes or until smooth. Take a small piece of dough and do the 'windowpane' test: if you can stretch it relatively thinly without tearing it, that means the gluten has developed enough. If it tears, knead for a bit longer and try again.
3. Put the dough in a medium bowl, cover with a clean damp cloth and leave the dough to prove for 1–1½ hours or until it has nearly doubled in size. The proving time will depend on the temperature in the room – the warmer it is, the less time it will need.
4. Gently knock back the dough, then roll it into a cylinder for portioning. Divide the dough into eight even pieces and roll into balls. Place on a tray, cover with clean dry cloth and prove for an hour until doubled in size.
5. Preheat the oven to 200°C.
6. To make the topping, combine the baking soda, flour and sugar in a bowl. Add the egg, milk, lard and ½ teaspoon water and mix until just combined (do not overwork the dough). Cover the dough with plastic wrap and rest in the fridge for 30 minutes.
7. Cut the pastry topping into eight walnut-sized balls Lightly dust the surface with flour, then press down on each ball to form a thin disc. Place a disc on top of each bun.
8. Lightly spray the buns and topping with water, then brush the topping with the beaten egg yolk. Bake for about 15 minutes or until the buns are raised and golden brown. Cut in half and serve warm with a slice of good-quality butter. The buns are best eaten on the day they're made, but can be stored in an airtight container and eaten the next day.