Preheat oven to 350 degrees F.

Combine flour, salt and brown sugar. 

Cut in the butter with a pastry blender or fork until the mixture is crumbly. 

Add the eggs and stir to incorporate. Stir in 1 ½ cups of the chocolate chips. 

Set aside 1 ½ cups of the dough. Press the remaining dough into a 9×13'' baking pan lined with parchment paper or greased lightly with cooking spray. Bake for 10 minutes.

Remove from oven and pour the sweetened condensed milk evenly over the warm baked crust. Gently spread it into an even layer.

Reserve ⅓ cup of the toffee bits and then sprinkle the remaining toffee bits on top. 

Dollop the remaining dough over the toffee bits. Sprinkle with remaining chocolate chips and toffee bits.

Bake for 25-30 more minutes, or till golden brown. Cool completely before serving.

I think they taste even better the next day! Cool completely and store, covered, in the fridge.