3/4 cup plus 2 tablespoons flour
1/4 teaspoon baking powder
1/2 teaspoon salt
4 ounces semisweet chocolate, chopped
1 stick unsalted butter, cut 1/2 inch pieces
1 cup brown sugar, packed
1 teaspoon vanilla
2 large eggs
CARMEL PECAN LAYER
3/4 cup sugar
1/3 cup light corn syrup
3 tablespoons water
1/3 cup heavy cream
1 teaspoon vanilla
1 1/2 cups pecans
Preheat oven to 350 degrees. Butter and flour a 9 inch square metal baking pan, knocking out excess flour.
Whisk together flour, baking powder and salt in a small bowl.
Melt chocolates and butter in a 2 quart heavy saucepan over low heat, stirring until smooth, then remove from heat. Cool to lukewarm, then stir in brown sugar and vanilla. Add eggs 1 at a time, beating with a wooden spoon after each addition until mixture is glossy and smooth. Add flour mixture and stir until just combined.
Spread batter evening in baking pan and bake in middle of oven until a tester comes out clean, 30-35 minutes. Cool completely in pan on a rack.
For caramel mixture; Bring sugar, corn syrup, water, and a pinch of salt to a boil in a 3 quart heavy saucepan over moderate heat, stirring until sugar is dissolved, then boil, without stirring, until mixture turns a golden caramel color, about 10 minutes. Remove from heat and carefully add cream and vanilla (mixture will bubble and steam). Stir in pecans and immediately pour over browning layer, spreading evenly. Cool completely in pan on rack.
Spoon some melted semisweet chocolate into a small sealable plastic bag and seal, forcing out excess air. Squeeze chocolate into 1 corner, then cut a tiny slice off corner to form a small hole. Squeeze chocolate decoratively over brownies.
Chill brownies, loosely covered, until caramel and chocolate are firm, at least 4 hours. Just before serving, cut chilled brownies into 64 one inch squares and remove from pan while still cold, then bring to room temperature.