Giant Chocolate Toffee Cookies

1/2 Cup all purpose flour 1/4 tsp salt 1 tsp baking powder 1/4 Cup butter (1/2 stick) 1 lb bittersweet (not unsweetened) or semisweet chocolate, chopped 1 3/4 Cup (packed) brown sugar 4 large eggs 1 Tbsp vanilla extract 5 chocolate covered english toffee bars (1.4 ounce) coarsely chopped 1 Cup walnuts, toasted, chopped (optional)
  • Combine flour, baking powder, salt in small bowl; whisk to blend.
  • Stir chocolate and butter in top of double boiler set over simmering water until melted and smooth. Remove from water. Cool mixture to lukewarm. (Microwave melting technique acceptable.)
  • Using an electric mixer, beat sugar and eggs in bowl until thick, about 5 min.
  • Beat in chocolate mixture and vanilla. Stir in flour mixture, then toffee and nuts. Chill batter until firm - about 45 minutes.
  • Preheat oven to 350 F. Line 2 large baking sheets with parchment paper or waxed paper. Drop batter 1/4 Cup onto sheets, spacing 2 1/2" apart. Alternate: grease cookie sheet with crisco. Bake at 305 F convection for 10 minutes.
  • Bake until tops are dry and cracked but cookies are still soft to touch, about 15 minutes. Cool on sheets.
  • Can be made 2 days ahead. Store airtight at room temperature.