0.5 cup hazelnuts peeled lightly toasted chopped for sprinkling, if desired*
0.3 teaspoon kosher salt
0.5 cup sugar
8 tablespoons butter unsalted cut into pieces
0.5 teaspoon vanilla extract
Equipment
food processor
baking sheet
baking paper
oven
wire rack
plastic wrap
double boiler
cookie cutter
microwave
Directions
Process 1/2 cup toasted chopped hazelnuts and next 4 ingredients in a food processor until nuts are finely ground.
Add butter, vanilla, and egg yolk; pulse until butter is cut in evenly and mixture starts to come together, scraping down sides of machine once or twice. (Dough will be very crumbly and may not come together fully until kneaded.)
Remove dough from processor, and knead lightly 2 or 3 times. Flatten into a disc, wrap with plastic wrap, and chill at least 2 hours or up to 3 days.
Remove from refrigerator 10 minutes prior to rolling.
Preheat oven to 35
Roll dough to 1/4-inch thickness on a lightly floured surface.
Cut heart shapes with a 2 1/2-inch cookie cutter, and place on a parchment paper-lined baking sheet. Gather and reroll dough scraps, and cut again.
Bake 10 to 12 minutes or just until edges turn light golden brown.
Remove from oven, transfer cookies to a wire rack, and cool completely.
Melt chocolate in a double boiler over low heat, stirring often, or in a microwave at HIGH 1 1/2 to 2 minutes, stirring every 30 seconds. Cool slightly. Dip half of each cookie into melted chocolate, and place on parchment paper-lined baking sheet.
Sprinkle with chopped hazelnuts, if desired, and chill about 15 minutes or just until chocolate sets.
Remove from refrigerator, and store in a single layer in an airtight container up to 2 days.
*To peel hazelnuts, roast at 350 for 6 to 8 minutes, and rub in a towel while warm to remove skins.
**For testing purposes, we used Scharffen Berger chocolate.