-
1
Lightly oil an 8-inch square baking pan and line with plastic wrap, allowing a 2-inch overhang.
-
2
Toast and skin hazelnuts.
-
3
In a food processor pulse hazelnuts until finely chopped, about 30 seconds.
-
4
Chop chocolates into 1/4-inch pieces, reserving 1 slightly mounded tablespoon bittersweet chocolate for tempering.
-
5
In a double boiler or a metal pan set over a saucepan of barely simmering water melt three fourths of chocolate, stirring until smooth.
-
6
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.
-
7
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.
-
8
If chocolate is too warm, add reserved chocolate, stirring until smooth.
-
9
Stir hazelnuts and hazelnut butter into chocolate until combined well and spread mixture in pan.
-
10
Chill confection, covered with plastic wrap, until firm, at least 2 hours.
-
11
Lift confection out of pan and peel off plastic wrap.
-
12
On a cutting board with a sharp large knife cut confection lengthwise into 1-inch strips and cut strips crosswise into 1-inch squares.
-
13
Chocolates keep, covered and chilled, 1 month.
