1 Preheat the oven to 180°C. Mix the mustard and honey together and season to taste.

2 Enlarge the hollow left by the bone in each chicken thigh, cutting to open them out. Press to flatten them a little. Place the thighs, smooth side up, in a lightly oiled ovenproof dish or small roasting pan. Set aside about 2 tablespoons of the honey and mustard mixture, and spread the remainder over the top of the chicken thighs. Roast for 12–15 minutes or until the juices run clear when a thigh is pierced with a knife.

3 Meanwhile, split open the buns and toast them. Place a lettuce leaf on the bottom half of each bun, top with the mango slices and sprinkle with the spring onions, if using. Spread the reserved honey and mustard mixture over the underside of the top halves.

4 Put the roast chicken thighs on top of the mango and spring onions, then top with the remaining lettuce. Put the tops of the buns on and press the sandwiches gently together. Serve immediately.