Cut in butter until mixture resembles coarse crumbs.
Add egg and mix well.
Reserve 1 1/2 cups of this mixture and press remaining into a greased 9x13 inch pan.
Bake for 10 minutes at 350 degrees F.
Pour sweetened condensed milk over hot crust and top with 1 1/2 cups toffee bits.
Stir in 1 1/2 c. chocolate chips into reserved crumb mixture
Sprinkle mixture over the top of the bars.
Bake 25-30 more minutes.
While hot out of the oven, top with remaining toffee bits.
Video
Notes
How to Freeze:Freeze entire pan: Before baking, line the baking dish with parchment paper that goes up the sides of the pan. After baking, using the parchment paper, remove the brownies from the pan and allow to cool completely. Double wrap with the entire thing in plastic wrap and then foil and freeze for 2-3 months. Thaw at room temperature or overnight in the refrigerator before slicing and serving. Freeze individual bar cookies: Bake, cool and slice. Wrap individual bar cookies in plastic wrap and then in foil or place in an airtight container. They will freeze for 2-3 months. Thaw at room temperature for 1-2 hours.