Chocolate Toffee Bars

1 3/4 cups unsifted flour
3/4 cup firmly packed brown sugar
3/4 cup cold butter or margarine
1 (14 ounce) can chocolate sweetened condensed milk
1 egg
1 teaspoon vanilla extract
6 (1.4 ounce) milk chocolate-covered English
    toffee candy bars, cut into small pieces
1 cup chopped nuts (optional)

Preheat oven to 350 degrees F (325 degrees F for glass dish).

In medium bowl, combine flour and sugar; cut in butter until crumbly. Press firmly on bottom of 13 x 9-inch baking pan. Bake 15 minutes.

Meanwhile, in medium bowl, combine sweetened condensed milk, egg and vanilla extract; mix well. Spread evenly over prepared crust. Top with toffee pieces and nuts if desired. Bake 20 to 25 minutes longer or until bubbly. Cool. Cut into bars. Store covered in refrigerator.