Line and grease a 20cm square cake tin. Cream the sugar and butter together till light and fluffy, and then beat in the eggs, one at a time, adding in the ground almonds with the last egg. Mix in the lemon zest and juice, the almond essence, and then fold in the flour. Next, carefully fold in ¾ of the blueberries and raspberries. Pour the cake mixture into the prepared cake tin, flatten out, and then scatter the remaining berries over the top of the cake. Bake in the middle shelf of the oven at 180`c, till the cake is firm in the middle. Meanwhile, make the lemon syrup by placing the water, sugar, lemon zest and juice in a saucepan. Bring the liquid to the boil, and continue to cook till the sugar dissolves and you are left with a thick syrup. Remove off the heat and put to one side. When the cake is cooked, take it out of the oven and prick the top all over with a skewer. Quickly pour the lemon syrup over the top, and allow the cake to soak up all the syrup. For best results, serve the raspberry and blueberry cake when it has completely cooled down. (Serves 14)