Prepare the vegetables and place in a roasting tin, pour over the olive oil and spices and mix well.
Place the vegetables in the oven and bake for 45 minutes, stirring once.
Meanwhile, put the couscous into an ovenproof bowl. Add water until it is level with the top of the couscous. Leave it to soak for 5 minutes.
Cut the butter up into tiny cubes and sprinkle over the couscous. Season with salt and pepper, then cover with foil and bake in the oven for 20 minutes.
When both the vegetables and couscous are ready, stir the vegetables into the couscous, together with the cilantro.
Notes
This roast vegetable couscous is delicious served warm or cold.