These chocolatey cookies are rolled in an icing sugar coating, creating a a snow-dusted crinkled cookiescape.
The cookies will keep up to 5 days in an airtight container.
Preheat the oven to 375 ºF (190 ºC). Line 2 baking trays with parchment paper.
Melt 6 oz (180 g) of the chocolate in a metal bowl placed over a saucepan filled with an inch of barely simmering water, stirring gently until melted. Set aside.
With electric beaters or in a stand mixer fitted with the whip attachment, whip the eggs with the granulated sugar, vanilla and Balsamic until frothy and light, about 3 minutes (it doesn’t have to hold a “ribbon”). Whisk in the melted chocolate.
Sift in the icing sugar, cocoa powder, cornstarch and salt and stir in by hand until well combined. Stir in the remaining 3 oz (90 g) of chopped chocolate. The batter may seem very soft at first, but just give it a minute – it will tighten up.
Place some icing sugar in a shallow dish. Use a small ice cream scoop to scoop the batter and drop it directly into the icing sugar, rolling to coat each scoop fully. Arrange these on the prepared baking trays, leaving 1 ½-inches (4 cm) between them. Gently press each cookie flat with the palm of your hand. Bake the cookies for 10 minutes (do not overbake) and cool the cookies on the tray just until they can be lifted off (1-2 minutes) then cool on a rack.