In a large bowl, cream butter and sugar. Add the eggs, milk and mix well. Combine the flour, baking powder and salt; gradually add to creamed mixture, beating just until combined. Divide dough into four 2-cup portions. Cover and refrigerate.
Basic Cookie Dough may be used to prepare the following recipes: Crumb-Topped Date Bars, Cherry Surprise Cookies, Chocolate Mallow Cookies or Jelly Sandwich Cookies. Yield: 8 cups.