How to Remove Skins and Toast Hazelnuts
Toasting hazelnuts bring out the flavor of the nut, but the skins are bitter and need to be removed as best as possible. Below are two techniques for accomplishing this:
Fill a large saucepan no more than 1/2 full with water. Bring to a boil. Add hazelnuts and 1 tablespoon of baking soda. Be careful, if there is too much water in the pan it might boil over when the soda is added. Boil for 3 to 5 minutes.
Drain them in a colander and run cool water over them. As you do this the skins will start sliding off with a gentle rub. You can either leave the hazelnuts in the colander and continue gently rubbing off the skins with your hands under running water or place the hazelnut in a dish towel and gently rub off the skins using the towel.
To toast using an oven: Spread the blanched nuts (either whole or chopped) evenly in a shallow pan. Bake in preheated 350°F (177°C) oven 7 to 15 minutes or until golden brown. Stir frequently; do not leave unchecked.
To toast on top of the stove: Place blanched nuts (either whole or chopped) evenly in a dry skillet. Cook over medium heat and cook, stirring or shaking the pan frequently to prevent burning. Take from pan when the nuts begin to release their flavor, about 4 minutes.
Preheat oven to 350°F (177°C). Place hazelnut on baking pan in one layer. Place pan in the middle of the oven and bake for 10 to 15 minutes, or until lightly colored and skins are blistered and start to crack.
Spread a rigid dish towel or tea towel across the counter. Remove the baking pan from the oven and carefully turn out the nuts onto the dish towel. Bring the ends of the dish towel up around the hazelnuts and wrap them up like a present. Let the nuts steam within the towel for at least a minute. Using your hands, gently rub the still-hot hazelnuts between the towel and the countertop (or between your hands) so that the friction created by the rubbing loosens the skin (don't worry about skins that don't come off). If the nuts are very hot, you may want to wear oven mitts while you press down on the towel. Once the skins have been removed allow the nuts to cool completely.
Make sure to take the hazelnuts out of the oven while they are on the light side, as they will darken more as they cool. Also, when hazelnuts are added to hot melted chocolate or caramel, the heat will brown the nuts further.
Let toasted nuts cool completely before using.
Toasted hazelnuts can be stored, covered, in a cool, dry place for up to 2 weeks.