1/2 cup flour
1 teaspoon baking powder
Dash of salt
1 pound (16 ounces) semisweet chocolate, chopped
1/4 cup (1/2 stick) butter
1 3/4 cups brown sugar
4 large eggs
1 tablespoon vanilla
5 1.4-ounce Heath bars, coarsely chopped
1 cup walnuts, toasted, chopped
Combine flour, baking powder and salt in small bowl; whisk to blend.Gently melt butter and chocolate in microwave. 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 a hour.
Preheat oven to 350°F. Line 2 large baking sheets with parchment. Drop batter tablespoonfuls onto sheets, spacing 2 1/2 inches apart. Bake just until tops are dry and cracked but cookies are still soft to touch, about 9 minutes. Cool on sheets.Store airtight at room temperature.