Bring 6 cups of water to a boil in a large saucepan with a pinch of salt and the chili. As soon as the water boils, add the sorrel and simmer for 10 minutes. In a soup tureen whisk together the lemon juice and egg yolks. Little by little, add ladlefuls of the sorrel mixture to the tureen and stir to mix. Refrigerate for several hours or overnight. Before serving, stir in the hard-boiled eggs, cucumber slices and crushed garlic. Add 2 ice cubes to the soup per person.
