3 cups pecans (12 oz), toasted and cooled , then coarsely chopped
2 oz fine-quality bittersweet chocolate (not unsweetened), very finely chopped
Special equipment: a candy thermometer
Directions
Preheat oven to 350°F.
Line a 15- by 10-inch shallow baking pan (1 inch deep) with foil, leaving a 2-inch overhang on the 2 short sides. Butter all 4 sides (but not bottom).
Blend flour, brown sugar, and salt in a food processor, then add butter and pulse until mixture begins to form small (roughly pea-size) lumps. Sprinkle into baking pan, then press down firmly all over with a metal spatula to form an even layer. Bake in middle of oven until golden and firm to the touch, 15 to 17 minutes, then cool in pan on a rack.
Melt butter in a 3-quart heavy saucepan over moderate heat and stir in sugar, corn syrup, and salt. Boil over moderately high heat, stirring occasionally, until caramel registers 245°F on thermometer, about 8 minutes. Carefully stir in cranberries, then boil until caramel returns to 245°F. Remove from heat and stir in vanilla, then stir in pecans until well coated. Working quickly, spread caramel topping over base, using a fork to distribute nuts and berries evenly. Cool completely.
Lift bars in foil from pan and transfer to a cutting board. Cut into 6 crosswise strips, then 6 lengthwise strips to form 36 bars.
Melt half of chocolate in top of a double boiler or a metal bowl set over a saucepan of barely simmering water, stirring until smooth. Remove bowl from heat and add remaining chocolate, stirring until smooth. Transfer chocolate to a small heavy-duty sealable plastic bag. Seal bag and snip off a tiny piece of 1 corner to form a small hole, then pipe chocolate decoratively over bars. Let stand at room temperature until chocolate sets, about 1 hour.
