Pineapple Pastels

Heat milk in a small saucepan over medium–low heat until lukewarm. Remove from heat, stir in yeast, then stand in a warm place for 7 minutes or until starting to foam.
Place flour, sugar and 1 tsp salt in the bowl of an electric mixer fitted with a dough hook attachment and mix to combine. Add 2 eggs and yeast mixture, then knead on low speed for 2 minutes or until a dough forms. Increase speed to medium, then add butter in 3 batches. Knead for a further 8 minutes or until mixture is smooth and elastic; it will be quite sticky. Transfer to a lightly oiled bowl, cover and stand in a warm, draught-free place for 1½ hours or until dough doubles in size.
Meanwhile, to make pineapple yema, place condensed milk, egg yolks and pineapple juice in a large heatproof bowl, whisking until well combined. Place over a saucepan of gently simmering water, making sure the bowl doesn’t touch the water. Add butter and cook, whisking constantly, for 10 minutes or until very thick and almost paste-like. Cool slightly, then cover and refrigerate until needed.
Preheat oven to 180°C. Grease 12 x 7 cm dariole moulds with extra melted butter and place on 2 oven trays. Lightly beat remaining egg in a bowl. Knock down dough, divide into 12 pieces, then shape into balls. Place balls in moulds, brush with beaten egg, then cover with a sheet of baking paper. Set aside for 30 minutes or until dough doubles in size. Alternatively, use 6 x 7 cm moulds and bake buns in 2 batches.
Bake buns, covered with baking paper, swapping trays halfway, for 15 minutes or until golden and risen. Cool buns in moulds for 10 minutes, then run a knife around moulds to release buns and cool completely on a wire rack.
Fill a piping bag fitted with a 1 cm nozzle with pineapple yema. Using a small sharp knife, make a small incision halfway up the side of the buns, then wiggle the knife gently to make a hole in the middle. Insert nozzle and pipe in the yema. Serve immediately.