1. Preheat oven to 375. Make crust: Put butter and brown sugar into the bowl of an electric mixer fitted with the paddle attachment; mix on medium speed until light and fluffy, about 2 minutes. Mix in salt. Add flour, 1 cup at a time, mixing until fully incorporated after each addition. Continue mixing until dough begins to come together in large clumps.
2. Press dough about 1/4 inch thick into a 9 by 13 inch baking pan. Pierce the dough with a fork. Chill until firm, about 20 minutes. bake until golden brown, 18 to 20 minutes. Transfer to a wire rack to cool completely. Reduce oven to 325F.
3. Make filling: Place butter, brown sugar, honey, granulated sugar, and heavy cream in a saucepan over high heat. Bring to a boil, stirring constantly until mixture coats the back of a spoon, about 1 minute. Remove pan from heat; stir in salt, nuts, and vanilla. Pour filling into the cooled crust.
4. Bake until filling bubbles, 15 to 20 minutes. Carefully transfer to a wire rack to cool completely. Run a paring knife around edges of the pan and invert onto cooling rack. Invert again onto a cutting board. Use a sharp knife to cut into 1 by 3 inch bars. Bars can be stored in an airtight container at room temperature up to 1 week. |