Place the flour (450 g), caster sugar (2 tbsp), salt (½ tsp), and yeast (2 tsp) in a bowl and mix together.
Add the milk (3 tbsp), warm water (210 ml) and butter (42 g) to a jug and stir together until the butter melts. Stir the liquid mixture into the flour mixture, first with a spoon and then in a mixer fitted with a dough hook.
Place the dough in an oiled bowl. Cover with glad wrap until doubled in size – about 90 minutes to 2 hours.
After the dough has proved, tip it out of the bowl onto a floured surface, and split it into 10 balls (80g). Place a piece of baking paper on your work surface and roll each ball into an oval on top of the parchment, using a rolling pin – approx. 12cm x 8cm.
Brush the ovals with the olive oil (1 tbsp) and fold each oval over, using a chopstick in the middle to fold over to leave a little space in the fold (so the oil is on the inside of the fold). Remove the chopstick.
Prepare two oven trays by lining each with a piece of baking parchment. Place the buns on the trays – still on the baking parchment – as this will help you to move them later. Cover each tray with glad wrap and leave to prove for a further hour, until puffed up.
Steam for 15 minutes.
Makes 6 burger buns (130g)