Toffee Bars

TOFFEE BARS 1 c. salted butter 1 c. dark brown sugar 1 large egg yolk 1 tsp. pure vanilla extract 1/4 tsp. salt 2 c. all-purpose flour 1 c. semisweet chocolate chips 1/2 c. finely diced walnuts Cream butter and sugar. Add egg yolk and vanilla; mix well. Add flour and salt, mixing until just combined. Spread into parchment-lined quarter-sheet pan (or 9x13). Bake at 350 for 25 minutes, or until lightly browned. Once pan is out of the oven, immediately sprinkle on chocolate chips; let sit for 5 minutes to allow chips to soften. Using an offset spatula, spread softened chips into an even layer. Top with nuts. Let cool until chocolate is almost set before slicing.