Preheat oven to 350°F. Prepare a 9”x13” baking dish with aluminum foil, leaving an overhang on the edges for easy removal.In a medium bowl, use an electric hand mixer to cream together ¾ cup butter and sugar. Add flour and mix until combined.Firmly press mixture into the prepared baking dish. Bake 15-20 minutes, until edges are just starting to brown.Meanwhile, in a small saucepan over low heat, add caramels, milk and 2 tablespoons butter. Cook until caramels are smooth and melted. Allow to cool slightly.In a medium bowl, combine brown sugar, eggs, vanilla and salt. Gradually mix in the caramel mixture, then stir in pecans. Pour filling over warm crust.Bake 25-30 minutes, until filling is set. Allow to cool completely, then refrigerate 1-4 hours.Sprinkle with flaky salt and serve. Refrigerate leftovers up to 3 days.