Toasted ground hazelnuts make the cookie dough extra rich. The crescents are shaped by hand and drizzled with both semisweet and white chocolate for a truly exquisite cookie.
1. In large bowl, beat butter, both sugars, 1 tablespoon water, vanilla, nutmeg and salt at low speed for 2 minutes. Scrape down bowl. Beat at medium-low until fluffy, 2 minutes. Beat in yolk, then ground hazelnuts. At lowest speed, beat in flour, just until blended. Dough should be stiff, but still soft; add a little more flour if needed.
2. Turn out onto floured surface. Divide in half. Shape each into a block, 1-inch thick. Wrap in plastic. Refrigerate 1 hour.
3. Heat oven to 350 degrees F. Break off 2 tablespoons of dough. Warm slightly with hands and roll to a 3-inch log. Curve ends to form a crescent. Space 1 inch apart on ungreased baking sheets. Repeat for a total of 48.
4. Bake at 350 degrees F for 13 to 15 minutes, until uniformly tan. Cool on wire racks.Drizzle:
5. Set racks over sheets of parchment or waxed paper. Place melted semisweet and white chocolates in two resealable plastic bags. Snip off a small corner of each. Drizzle over cookies; let harden.