Combine butter and the 1 cup powdered sugar in a large mixing bowl. Beat with an electric mixer on medium speed for 3 minutes. Add egg yolks and vanilla and beat until well mixed. Gradually beat in the flout. Stir in potato chips and pecans with a wooden spoon. Drop by rounded teaspoonfuls onto a greased cookie sheet. Bake in a 350 degree oven for 10 minutes. Transfer to a wire rack. While cookies are still warm sift with powdered sugar. Cool completely. Store in airtight containers. Makes about 40 Posted to FOODWINE Digest 24 Jan 97 by Don Barry on Jan 23, 1997.