Mix like pie crust the flour, shortening and brown sugar. Reserve ¾ c. for topping. Mix together the egg, milk, soda and vanilla. Pour into crumb mixture and let stand about 5 minutes. Beat with mixer until smooth. Batter will be thin. Pour into greased and floured 9 x 13 inch pan.
Sprinkle crumb mixture over batter, then the ½ c. chopped nuts. Break up Heath bars and sprinkle over all. Bake at 350 degrees for 30 minutes or until done.