Heat your oven to 200°C/Fan 180°C/Gas 6. Peel the onion and slice it into thick wedges. Halve the pepper. Scoop out the seeds and white bits, then thickly slice. Halve and thickly slice the courgette.
Chuck all the veg into a roasting tin. Peel and finely chop the garlic. Finely chop the chilli, flicking out the seeds for a milder heat. Finely chop the parsley stalks (keep the leaves for later).
Add the garlic, chilli and parsley stalks to the veg with 1 tbsp oil and plenty of salt and pepper. Stir to coat the veg in the oil and seasoning. Roast for 40 mins till the veg are tender and a little charred.
While the veg roast, tip the couscous into a heatproof bowl. Pour over 200ml boiling water. Cover the bowl with cling film or a plate and set aside for the water to absorb.
When the veg are 10 mins away from being done, rub 1 tsp oil and some seasoning into each minute steak. Heat a griddle or frying pan till it’s smoking hot. Add the steaks. Fry for 1-3 mins on each side, depending on how well done you like your steaks.
Slide the steaks onto a warm plate. Cover with foil. Leave to rest for 5 mins.
Stir the couscous into the roast veg. Finely grate the zest from the lemon and stir that in too. Add a squeeze of lemon juice. Serve the couscous with the steaks, garnished with the parsley leaves.