Gianduia Chocolates

Lightly oil an 8-inch square baking pan and line with plastic wrap, allowing a 2-inch overhang.

Toast and skin hazelnuts. In a food processor pulse hazelnuts until finely chopped, about 30 seconds. Chop chocolates into 1/4-inch pieces, reserving 1 slightly mounded tablespoon bittersweet chocolate for tempering. In a double boiler or a metal pan set over a saucepan of barely simmering water melt three fourths of chocolate, stirring until smooth.

Remove top of double boiler or bowl from heat and add remaining chocolate in 2 or 3 batches, stirring until smooth and allowing each batch to melt before adding next.

When all of chocolate is melted, test its temperature: Put a dab of chocolate on the inside of your lower lip; it should be slightly cooler than your body temperature. If chocolate is too warm, add reserved chocolate, stirring until smooth.

Stir hazelnuts and hazelnut butter into chocolate until combined well and spread mixture in pan. Chill confection, covered with plastic wrap, until firm, at least 2 hours. Lift confection out of pan and peel off plastic wrap. On a cutting board with a sharp large knife cut confection lengthwise into 1-inch strips and cut strips crosswise into 1-inch squares. Chocolates keep, covered and chilled, 1 month.