Preheat oven to 325 degrees.Butter the bottom of a 9x13 baking pan.Line with parchment paper and butter that also.
To make shortbread,measure the flour,1/2 c. of brown sugar and 1/2 tsp. salt,in a food processor.Pulse till mixed. Add 1 c.of the butter,cut in chunks,and pulse till roughly mixed.Sprinkle in 1/2 to 1 tsp. vanilla.Continue to pulse till mixture forms a ball.Remove and place in baking dish,pat with hands to cover bottom.Bake35to40 min,turning halfway through baking time so shortbread browns evenly.I usually let mine get very light brown,to brown and it gets very hard.
To make the caramel melt 1 cup butter,over low heat.Stir in 1 c.brown sugar,the corn syrup,and the condensed milk.Raise heat and bring to a boil,slowly, stir constantly, and boil for 4 minutes.Remove from heat and stir in vanilla.Pour evenly over crust.Smooth to cover all.
Melt the chocolate and spread over caramel.Cool completely in pan,then using the parchment paper,remove from pan.I have found that
if you try to remove it when caramel is not set, you will have a real mess on your hands. Lucky for me I havent had that happen.
After you remove bars to your counter, I have found that a long sharp knife really works best.I did not include my recipe for the way I do my chocolate.I add heavy cream or half and half to my chocolate just to smooth it out.The choice is yours.Hope you enjoy.