Chicken burger with avocado and blue cheese

Method

1. In a bowl, mix the mince, chopped onion, mustard, 2 tablespoons soured cream, ketchup and the zest. With wet hands, season and shape into 4-6 burgers. Chill the burgers for 1 hour to firm up. Toss the red onion with the lemon juice in a bowl. Set aside.
2. Heat a griddle pan until hot. Brush the burgers with the oil and griddle for about 5 minutes each side, until golden and cooked through.
3. Preheat the grill to medium. To serve, split the buns and toast on the griddle pan. Spoon a tablespoon of the soured cream on each bun base and top with the lettuces, burgers, then the avocado, onion and cheese. Place under the grill for a few minutes until the cheese is melted.