If you have gas hobs, turn two of them on. Rest the aubergines on the hobs so the flames just touch them. Cook them like this for about 10 mins, turning every so often with tongs, till the aubergines are charred and soft.
No gas hob? Heat your grill to high and grill the aubergines whole, turning now and then, for 15 mins till charred and soft. Put to one side to cool.
Peel and finely chop the onion. Peel and crush the garlic. Warm 1 tbsp olive oil in a deep frying pan or wok. Add the onion. Season. Cook over a low heat for 5 mins till the onion is soft and glossy but not too coloured. Stir now and then.
While the onion cooks, peel the skin off the aubergines. Roughly chop the flesh.
Stir the garlic into the onion. Measure out 1 tsp ground cumin and add that with a pinch of the harissa (it’s spicy, so start with a small pinch and add more later if you think it needs it). Cook and stir for 1 min.
Stir the aubergines into the onion. Add the chopped tomatoes and half the oregano leaves. Add 200ml boiling water. Stir the sauce together, then cover. Simmer for 10 mins till it starts to thicken.
Taste the sauce and adjust the seasoning. Make four holes in the sauce. Crack an egg into a cup or bowl and slide it into each of the holes.
Put the lid back on the pan. Cook over a medium heat for 5-8 mins till the eggs are just set. Serve the shakshuka in bowls sprinkled with a pinch more of the harissa and some oregano leaves.