Gianduia Brownies

Source: Gourmet - February 1998

1 1/4 cups hazelnuts (about 6 1/4 ounces)
4 ounces fine-quality bittersweet chocolate
    (not unsweetened)
3 ounces fine-quality milk chocolate
1 stick (1/2 cup) unsalted butter
1/4 cup Nutella*
1/2 cup all-purpose flour
1/2 teaspoon baking powder
1/2 cup granualted sugar
2 large eggs

*available at specialty foods shops and many supermarkets

Preheat oven to 350