Irish Lace Cookies

1 stick (1/2 cup) unsalted butter, softened
3/4 cup firmly packed light brown sugar
2 tablespoons all-purpose flour
2 tablespoons milk
1 teaspoon vanilla extract
1 1/4 cups old-fashioned rolled oats

In a bowl cream the butter with the brown sugar until light and fluffy and beat in the flour, milk and vanilla. Stir in the oats, drop rounded teaspoons of the dough about 3 inches apart onto ungreased baking sheets, and bake the cookies in batches in the middle of a preheated 350ºF. oven for 10 to 12 minutes, or until they are golden. Let the cookies stand on the sheets for 1 minute, or until they are just firm enough to be moved with a metal spatula. (If desired, turn the cookies upside down on the sheets, and, working quickly, roll them into cylinders on the sheets. If the cookies become too hard to roll, return them to the oven for a few seconds and let them soften.) Transfer the cookies to a rack and let them cool completely.
Makes about 40 cookies.