- Slice the lettuce in half, lengthways.
- To prepare the marinade, put the ingredients in a large bowl and whisk with a fork to combine.
- Place the lettuce in a bowl with the marinade and massage into the lettuce.
- Cover and leave in the fridge for at least 30 minutes.
- When the BBQ is hot, grill the romaine hearts until lightly browned on all sides, turning every minute or two until done.