Put the figs, kumquats, prunes, sugar, Cognac and lemon zest in a saucepan with 2 cups/500 ml water and bring to a boil. Cook until the fruits are plump and the sauce syrupy. Turn off the heat and let the fruit macerate for 30 minutes. Pour into a serving dish (a cut glass bowl looks lovely) and let cool. Serve with creme fraiche and toasted almonds, or with a big spoonful of vanilla ice cream.