Stuffed Artichokes with yogurt

1. To prepare the artichokes, cut off the stem to leave about 3 cm, and then peel the stem. Take off the outer two rings of leaves and slice the artichokes across to separate the base from the leaves. Trim it back to reveal the hairy 'choke' in the center of the bud. Remove this carefully with a teaspoon. Each artichoke must be rubbed over with half a lemon, and then kept in water that has had lemon juice added to it. The acidulated water stops them oxidizing and going brown.
2. In a heavy bottomed casserole, sauté the onions in the olive oil, add the artichokes, enough water to cover them, and some salt. Place a large plate on the top of the artichokes so to keep them submerged and bring the water to the simmering point. Simmer for approximately 30 minutes. When the artichokes are ready, remove them with a perforated spoon and keep them aside. Bring the liquid to the boiling point and reduce by 70 percent, or until you have approximately 150 ml of water. Let the water cool down and whisk the yogurt into the water. Pour it over the artichokes and sprinkle on the top the chopped dill.
Serve it at room temperature as a salad or with a leftover of cold meat(s) and grilled sourdough bread.