5 issues of BBC Good Food for £5
Cook the potatoes in boiling salted water for 15-20 mins until tender, then drain well and tip into a large bowl.
Tip the lemon juice, harissa, salt and pepper into a bowl and whisk well, then add the onion and olive oil and whisk again.
Pour over the potatoes and olives, toss well, then leave to cool. Can be covered and chilled for up to 1 day.