Tip the couscous into a heatproof bowl. Pour in enough boiling water to cover the couscous. Cover the bowl with a saucer. Put to one side to soak.
Peel and roughly chop the onion. Trim and roughly chop the aubergine. Halve the red pepper. Scoop out the seeds and white bits. Roughly chop it. Roughly chop the tomatoes.
Pop the aubergine into a bowl. Add 1 tbsp olive oil. Toss the aubergine to coat it in the oil. Spread out on a rack in the grill pan. Grill for 5-8 mins till the aubergine is golden. Turn once or twice.
Warm ½ tbsp olive oil in a pan while the aubergines are grilling. Add the onion. Season with salt and pepper. Cook and stir over medium heat for 5 mins till the onion is soft.
Add the aubergine, pepper and tomatoes to the pan. Add 2 tbsp cold water. Cover. Lower the heat. Gently simmer for 10 mins till tender.
Season the steaks with salt and pepper. Drizzle each with 1 tsp olive oil. Rub it into both sides.
Heat a griddle or frying pan till smoking hot. Add the steaks. Fry for 1-2 mins. Flip. Fry for another 1-2 mins. Slide the steaks onto a plate. Cover with foil. Rest for 2 mins. Serve with the couscous and ratatouille, garnished with mint.