Toffee Bars-Laurice

I got this recipe from my cousin Lisa....it's a good one!
1-can eagle brand
1 3/4 c. flour
3/4 c. brown sugar
3/4 c. cold butter
1 tsp. vanilla
1 egg
1 bag mini skor/heath bars chopped

Mix Flour, sugar, cut in butter. Press down in 9 X 13 greased pan. Cook 15 min. 350 metal, 325 glass until golden & bubbly on the edges. Add slices of butter if dry spots are on the crust when you pull out, & bake about 5 to 10 more min. Mix eagle brand, vanilla & egg, spread on top crust add chopped toffee pieces on top. Cook 15-25 more min. until bubbly-add any chopped nut if desire.