1 - step 1 Whizz half the avocado flesh with the yogurt, lime and lemon juice and seasoning.

2 - Dice the remaining avocado, then gently stir into the whizzed mix with most of the lime zest.

3 - Cover, then chill until ready to serve.

4 - step 2 Boil potatoes for 6 mins, then drain well and toss with olive oil, chilli powder and cumin seeds.

5 - Now set aside until half an hour before your guests arrive.

6 - step 3 Heat oven to 200C/180C fan/gas 6, then roast potatoes for about 30 mins, shaking the tray halfway, until golden and tender.

7 - Transfer the dip to one or two bowls, scatter with the remaining lime zest and serve with the hot potatoes, and tortilla chips for dipping.