Adapted from Yankee magazine. I think these cookies are just lovely and am hoping to make them this year. The pistachios provide lovely green specks of color, so although they would still taste nice with a different nut, you would lose the green-red holiday effect if you substitute. Sanding sugar is the coarse, sparkly sugar that is used to decorate cookies - unlike ordinary sugar, the crystals will stay whole and look like clear sparkly sprinkles on the cookie edges (you can also use red or green). Plan ahead as the dough must chill overnight.