Preheat oven to 350 degrees.
In food processor, combine ½ cup unsalted butter, 1/3 cup brown sugar, pinch of salt and flour. Pulse until well combined, about 8-10 times. The mixture will be very crumbly but should hold together when you grab some in your fist.
Line the bottom of an 8x8 pan with parchment or greased foil. Press the sugar and flour mixture into the bottom of the pan, pressing until well compacted. Bake for 20 minutes or until it barely starts to turn brown. Remove from oven and set aside, but maintain oven temperature.
When crust is done baking, bring remaining butter, sugar, salt and cream to a boil over high heat using a small saucepan. Stir until sugar dissolves and continue to boil for one minute, stirring constantly. Remove from heat and add vanilla.
Pour caramel over shortbread and sprinkle with pecans. Bake for 20 minutes (caramel should be bubbly and start to darken). Remove from oven and immediately top with chocolate chips. Allow to sit for five minutes to allow chocolate to melt. Spread chocolate over caramel with an offset spatula or the back of a spoon. Sprinkle with coarse sea salt, if desired. Chill for 20 minutes, carefully remove from pan and cut into squares.
