These crispy and delicious cookie bars are adapted from a recipe in the Great American Home Baking files. I've found that decreasing the amount of flour in the bottom crust yeilds a softer cookie (rocket science!) that keeps longer - and going halfsies on the chocolate chips and supplementing with butterscotch yields a much nicer flavor combination. My brown sugar was unexpectedly hardened, so I beat the egg whites with some maple syrup instead, and found the resulting meringue coating to be flavorful and equally sweet. The recipe below is the original.
Cream 1 stick of soft butter with 1 cup of sugar. Beat in two egg yolks, one at a time (reserve egg whites).
Mix together 1.5 cups flour, 1 tsp baking powder, and 1/2 tsp salt. Fold flour mixture into butter mixture. Press into a lightly greased 9x13 pan.
Sprinkle over top of firmly packed crust - 1 cup chopped walnuts, 1/4 cup chocolate chips, 1/4 cup butterscotch chips, 1 cup marshmallows.
Beat reserved egg whites at high speed until stiff peaks form. Fold in 1 cup firmly packed brown sugar. Spread over top of the layers in pan.
Bake at 350 for 35 minutes, or until a crust is formed. Cool completely and cut into squares.
