1 1/4 cups hazelnuts ( about 6 1/4 onces)
4 ounces fine-quality bittersweet chocolate ( not unsweetened)
3 ounces fine-quality milk chocolate
1/2 cup unsalted butter
1/4 cup nutella ( chocolate-hazelnut spread available at specialty foods shops and many supermarkets)
1/2 cup all-purpose flour
1/2 teaspoon baking powder
1/2 cup sugar
2 large eggs
Preheat oven to 350F F.
and butter and flour a 9-inch square baking pan, knocking out excess flour.
Toast and skin hazelnuts.
In a food processor pulse hazelnuts until coarsely ground (bits should be about 1/8 inch).
Chop chocolates into small pieces and in a double boiler or a metal bowl set over a saucepan of barely simmering water melt chocolates with butter and Nutella, stirring occasionally until smooth.
Remove top of double boiler or bowl from heat.
While chocolates are melting, into a bowl sift together flour, baking powder, and a pinch salt.
Whisk sugar into chocolate mixture until combined well.
Add eggs, whisking until mixture is glossy and smooth.
Stir in flour mixture and hazelnuts until just combined.
Pour batter into baking pan and bake in middle of oven 35 to 40 minutes, or until a tester comes out with moist crumbs adhering to it.
Cool brownies completely in pan on a rack and cut into 16 squares.
Brownies keep, layered between sheets of wax paper in an airtight container at cool room temperature, 5 days.
Time preparation: 20 min.
Time total: 60 min.