Instructions

1. Mix the oil and vinegar, then season with salt and pepper. Set aside.
2. Rinse and dry the salad leaves, then scatter them onto a large serving platter or two plates.
3. Add the tomatoes, halved if necessary.
4. Finely slice the onion, add to the salad.
5. Tear the mackerel into chunks and scatter over the salad.
6. Peel and cut the avocado into thin wedges. Arrange these on top of the salad and drizzle with the dressing just before serving.