Preheat the oven to 200°C, 180°C fan, gas mark 6.
Remove the cores from the peppers, along with the seeds and finely slice. Trim the aubergine and cut it into chunks then add both veg to a large tray. If using sweetcorn instead of the aubergine, place in a large pan of boiling, salted water and cook for 7-8 minutes, or until tender. Remove and keep to one side.
Sprinkle the veg with salt and pepper, drizzle with two tablespoons of the olive oil and roast for 30 minutes, or until starting to soften and char at the edges. For the final 10 minutes of cooking, add the cherry tomatoes to the pan, giving everything a good shuffle so that it sits in a single layer throughout.
Meanwhile, rinse the quinoa and tip into a large saucepan. Cook to packet instructions, adding 4 tablespoons of Bay’s Kitchen Concentrated Beef Stock into the water. When tender, drain and return to the pan, putting the lid back on. Leave to one side.
Get a griddle pan or barbeque nice and hot. Rub the remaining two tablespoons of olive oil on the steak and sprinkle both sides with salt. Cook the steak for 4-5 minutes on each side, or to your liking, then transfer to a plate or board to rest. If cooking sweetcorn, place the cobs in the same pan you used for the steak and cook for 2-3 minutes each side, or until charred and warmed through.
Make the dressing by combining all of the ingredients in a small bowl. Slice the steak into thin pieces.
To serve, fluff the quinoa with a fork and spoon onto a serving platter. Add the rocket, vegetables and tomatoes, olives and steak and sprinkle over the basil leaves. Serve with the dressing on the side.