Preheat the oven to 180°C. Cut the aubergine into cubes, the pepper into half and the onion into quarters. Scatter all the vegetables into a large baking tray, drizzle some olive oil over them, season with salt & pepper, then put the tray into the oven.
Bake for about 25 to 30 minutes, until the aubergine, onion & garlic are soft and the pepper's skin is golden.
Put the vegetables into a mixing bowl and cover with a plate. Rest for about 10 minutes.
Carefully remove the skin of the aubergine, onion and pepper, then discard these.Squeeze the roasted garlic out of its skin and discard the skin.
Put the vegetables into a blender together with the cooking juices, add the spices and chilli flakes (if used). Add the lemon juice and the coriander, then process until you get a course textured paste. Taste, then season if needed.
Serve at room temperature.