Drain the mandarins and pineapple pieces. Beat butter, sugar and salt until creamy. Gradually stir in the eggs and the grated lemon zest. Mix the flour and baking powder and stir into the fat and egg mixture. Add the sour cream and work it into a smooth dough. Spread the dough on a greased tray. Spread the fruits on top. Bake the cake in a preheated oven at 175 degrees for about 30-40 minutes. Let cool down.
Heat the apricot jam and strain it through a sieve. Brush the cake evenly with it. Sprinkle with desiccated coconut. To cut in pieces.