Chocolatey and chewy, these bars are best served with fun, family and friends.
Heat oven to 350°F (180°C).
In medium bowl, mix together flour and brown sugar; cut in cold butter until crumbly. Stir in 1/2 cup (125 mL) of the semi-sweet chocolate chips; press mixture into ungreased 13 x 9-inch (33 x 23 cm) baking pan. Bake 15 minutes.
Meanwhile, in large bowl, combine sweetened condensed milk, egg and vanilla. Stir in remaining 1-1/2 cups (375 mL) chips and nuts. Spread evenly over baked crust.
Bake 25 minutes or until golden brown. Cool completely in pan on wire rack. Cut into bars.