Preheat oven at 350-degrees. Line a 13x9 pan with foil and apply nonstick spray or butter.
In a large bowl, combine flour, brown sugar, and cinnamon. Add the butter and vanilla. Beat until it resembles coarse crumbs. Stir in 2/3 cup chocolate chips and the pecans. Distribute the crumbs across the bottom of the pan and press down evenly.
Bake for 25 to 30 minutes, until golden. Immediately sprinkle on the remaining 1 cup of milk chocolate chips. Let sit a minute or two to soften, then use an uneven spatula to spread chocolate across the crust. Sprinkle toffee bits on top.
Cool in pan on wire rack; if desired, place in fridge to speed the process. Once the pan is cool, use foil to move contents to a cutting board. Slice into bars. Keeps in fridge or at room temperature for up to 2 days.
OM NOM NOM!