1 1/2 cups flour
2 eggs
2/3 cup brown sugar
1/4 teaspoon baking soda
1/2 teaspoon baking powder
1 teaspoon vanilla
1/2 cup butter
1/2 teaspoon salt 

2/3 cup corn syrup
1/4 cup butter
2 teaspoons vanilla
12 ounces chocolate chips

Bake crust for 12 minutes at 350 degrees in a 9-by-13 pan, sprayed. Spread 3 cups mini marshmallows over crust and return to oven until fluffy.For topping: microwave all four ingredients for about two minutes. Add 2 cups Rice Krispies cereal. Mix. Pour over crust.