These buttery mounds are meltingly good, and not too sweet. Make up to 4 days ahead; store in a cookie jar or tightly sealed container.
Prep time: About 20 minutes Bake time: About 18 minutes Preheat the oven to 325 degrees. Line 2 cookie sheets with aluminum foil and set aside. Using a mixer, beat the butter, sugar, and salt together for about 4 minutes, or until light and fluffy. Add the vanilla and milk, and beat until smooth. Add the flour and walnuts, and mix gently on low speed just until dough holds together. Scoop out about a cup of dough and roll it into a log shape. The dough will appear crumbly at first, but it will soften from the heat of your hands. Cut off small pieces, about ½-inch thick, and roll each to form a 1-inch ball. Place the balls on cookie sheets, not touching. Bake about 20 minutes or until the balls are solid and just beginning to turn golden. Remove from the oven and let cool slightly. Put the confectioners' sugar in a bowl. Carefully roll slightly warm cookies in the sugar to coat. How kids can help: Measure ingredients; put ingredients in bowl; help roll dough into balls; roll cookies in sugar.