Combine flour, icing sugar, butter, vanilla and egg together in a large mixer bowl.
Beat on low speed of electric mixer until dough forms a ball.
Press dough into greased 15x10" jellyroll pan.
Mark dough into 54 squares (9 across and 6 down) with the tip of a sharp knife.
Press an imprint with your thumb or the base of a teaspoon in the center of each square.
Place about 1 tsp of jam in each imprint.
Bake at 400°F for 15 - 20 mins or until light golden.
Re-cut while still warm along the marked lines.
Cool.
Drizzle with the melted chocolate and let set.
