Preheat oven to 350 degrees
In a bowl combine your flour, oats, sugar and salt.
Use a pastry blender to cut in the butter until the mixture is crumbly.
Set aside 1/4 C of the mixture to use as a topping.
Press remaining crumbs into the bottom of an ungreased 9 x 13 pan. Bake for 10 minutes.
In a small pan warm up your dulce de leche until it is a good spreading consistency.
Spread dulce de leche over the top of the crust. Be gentle as you spread it so you don't lift up the crumb mixture.
Sprinkle with toffee bits and chocolate chips.
Sprinkle with remaining crumb mixture.
Bake 25-30 minutes or until golden brown.
Cool and enjoy!