Preheat the oven to 400°F. Meanwhile, remove and discard the seeds from the chillies; squeeze the juice from the limes; peel the avocados, remove their stones and chop them; and roughly chop the fresh cilantro leaves.

To make the guacamole, mash or blend the chillies, lime juice, avocado and cilantro until creamy but a bit chunky. Season with salt and pepper, and pour into a serving dish.

Brush the tortillas with the oil, season with salt and pepper and sprinkle with the thyme leaves. Lay them on a baking sheet–-don’t overlap them too much--and bake for 5 minutes until golden brown, then leave them to cool. Break into wedges if you like, and serve the crispy tortillas with the guacamole.