Preparation - Generously spray a 13" x 9" x 2" baking pan with non-stick cooking spray. Combine the flour and brown sugar in a large mixing bowl. Mix well. Add the butter or margerine and mix with a fork until the mixture resembles course crumbs. Remove 1 cup of the crumb mixture and reserve it for the topping. Add baking powder and salt to the remaining mixture; stir. Mix the milk, beaten egg and vanilla together in a separate bowl. Add this mixture to the dry mixture and mix well to form a smooth batter. Pour the batter into the prepared baking pan. Sprinkle the reserved crumb mixture over the batter. Combine the chocolate chips, butterscotch chips, coconut and chopped walnuts; sprinkle evenly over the crumb topped batter. Bake in a preheated oven at 350º for 35 minutes or until the topping is very lightly browned. Do not overbake. Remove from the oven and cool completely on a wire rack before cutting into squares. Store in an airtight container.
