Preheat the oven to 200°C.
Prick the aubergine all over with a knife, then place it in a baking tray. Roast for about 35-45 minutes until the aubergine’s flesh is soft. Take the tray out of the oven and let it cool in the tray, then open the skin and scoop the flesh out.
Put the flesh in a small food processor. Add the garlic, harissa,. Whiz for a few seconds, then add the herbs and whiz again until you get a smooth or coarse paste.
Season with salt and pepper, then add the lemon juice and zest.
Taste and adjust the seasoning to your liking.
Transfer it into a serving bowl and refrigerate until serving.