-
Combine flour, baking powder and 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 over water. Cool mixture to lukewarm.
-
Using electric mixer, beat sugar and eggs in bowl until thick, about 5 minutes. 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 or waxed paper.
-
Drop batter by 1/4 cupfuls onto sheets, spacing 2 1/2 inches apart. Bake just until tops are dry and cracked but cookies are still soft to touch, about 15 minutes.