Spicy potato tagine with olives

Recommended for gnocchi. King Edward - long and oval, with white-pink flesh; very good baked or roasted. Kipfler - long, cigar-shaped, light yellow flesh, rich creamy texture and great flavour; best boiled for a salad or roasted. Nicola - small oblong, with yellow flesh; this is an all-round variety.

Good for gnocchi. Pinkeye - round with pink-blue "eyes" and rich, sweet golden flesh; good for mash or salad, as well as a casserole or curry. Pontiac - round, white fleshed; excellent mashed, roasted or fried.

This Moroccan dish is adapted from Paula Wolfert's book The Slow Mediterranean Kitchen.

Peel and thickly slice 900g of yellow-fleshed potatoes and place them in a bowl of cold water.

In a heavy saucepan (or well-seasoned tagine) heat 3 tbsp of olive oil and fry a finely chopped onion for 3-4 mins, stirring. Add a chopped tomato, 1/4 teaspoon each of paprika, ground ginger and cumin, and 2 crushed garlic cloves. Stir for 2 mins. Add the drained potatoes, a bay leaf and a quarter of lemon (whole). Toss, then add a handful each of chopped parsley and coriander and a couple of good pinches of salt. Toss, then add 5 saffron threads and 1 1/2 cups of hot water. Bring to the boil, reduce the heat and simmer until the potatoes are tender - 40-50 min.

Transfer the potatoes to a warm serving dish and discard the lemon. Add 24 pitted green olives to the liquid remaining in the pot and boil until the juices have reduced to a thick sauce.

Pour over the potatoes and garnish with half a preserved lemon, chopped.

To serve