The Mexican Taco Cheeseburger

Grill burger on a medium heat for 12-14 minutes, turning occasionally. Ensure burger is piping hot throughout. Peel and slice red onions, heat red wine vinegar with caster sugar and mustard seeds, pour over sliced red onion and leave to cool. Shred iceberg lettuce and warm tortilla on a griddle pan. Place tortilla on a board and add lettuce, break burger into pieces and add to lettuce. Top with tomato salsa and guacamole. Finish with crumbled Mexicana cheese, crushed chillies and soured cream. Serve with fries