Mix and roll pastry and line small, shallow patty pans (in the US, can use mini-muffin tins). Place 1/2 tsp of jam in bottom of each tart. Cream together sugar and butter. Add Beaten eggs and almond extract. Fold in flour and ground almonds. Place spoonful on top of tarts and decorate with almond slivers (approx. 4-5). Bake at 375 for 10-15 minutes until tops are golden.