- 1/2 cup all purpose flour
- 1 teaspoon baking powder
- 1/2 teaspoon salt
- 1 pound bittersweet (not unsweetened) or semisweet chocolate, chopped
- 1/4 cup (1/2 stick) unsalted butter
- 1 3/4 cups (packed) brown sugar
- 4 large eggs
- 1 tablespoon vanilla extract
- 5 1.4-ounce chocolate-covered English toffee bars (such as Heath), coarsely chopped
- 1 cup walnuts, toasted, chopped
- 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. Cool on sheets. (Can be made 2 days ahead. Store airtight at room temperature.)