In the United States, these cookies are called snowballs, but in other parts of the world they're known as Mexican wedding cakes or Russian tea cakes. Whatever you call them, they're always chock-full of finely ground nuts (we use walnuts, but you could also try pecans, pistachios, almonds or even hazelnuts). In addition to shaping the dough into snowballs and crescent moons, kids can also cut it into crunchy stars.
Preheat the oven to 400 degrees. In a medium-sized bowl, cream the butter and 2/3 cup of the confectioners' sugar until it's light colored. Add the vanilla extract.
Stir in the flour, salt and finely ground walnuts until well combined (you may need to use your hands to mix the dough thoroughly). Place the balls 1 inch apart on an ungreased baking sheet.
To make Crescents, roll a tablespoon of the dough into a 1-by-3-inch cylinder (one of our young recipe testers liked calling them snakes). Shape and flatten the dough into a curve. For Snowballs, ask your child to roll the dough into 1-inch balls.
Bake the Crescent Moons for 10 to 12 minutes and the Snowballs for 12 to 14 minutes, or until lightly browned around the bottom. Cool for 2 to 4 minutes before dusting with most of the remaining confectioners' sugar (a fun job for children).
Once the cookies are completely cool, dust them again with the last bit of confectioners' sugar. Makes about 36 cookies.