Toffee Topped Bars

2 cups firmly packed brown sugar
2 cups all purpose flour
1/2 cup butter or margarine
1 tsp baking powder
1/2 tsp salt
1 tsp vanilla extract
1 cup milk
1 egg
1 cup semi-sweet chocolate chips
1/2 cup chopped walnuts
1/4 cup unsweetened flaked coconut (optional)

::Preheat oven to 350. Lightly grease a 13x9 inch baking pan
::In a large mixing bowl, mix together the brown sugar and flour
::Using a pastry cutter (or 2 knives) cut in the butter until mixture resembles coarse crumbs. Remove 1 cup of mixture and set aside,
::To mixture in large bowl, add baking powder and salt. Using a fork lightly beat in vanilla, milk and egg
::continue beating until a smooth batter forms. Pour batter into prepared baking pan
::In a small bowl, combine the chocolate chips and walnuts. Fold in the coconut
::Sprinkle reserved crumb mixture over top of batter in pan. Sprinkle with the chocolate chips and walnuts
::Using a long flat spatula spread topping evenly over the top of the batter in pan
::Bake bars for 35 minutes, or until a skewer (or toothpick) inserted in the center comes out clean
::Transfer pan to wire rack. Cool bars in pan completely before slicing