Preheat oven to 350˚F/180°C. In large bowl, cream butter and brown sugar until light and fluffy. Add vanilla; gradually beat in flour until smooth and blended. Press in ungreased 15 x 10-inch/38 x 25-cm baking pan. Bake for 25 minutes or until crust is golden. Remove from oven. Arrange chocolate bars evenly on the crust and wait until spreadable. Spread chocolate evenly over crust, then sprinkle with almonds. Let chocolate cool; cut into squares.
Makes 40 squares.