Combine first 3 ingredients in a heavy saucepan; cook over medium-low heat, stirring constantly, until chocolate and butter melt.
Remove from heat. Stir in vanilla, flour, and chopped pecans.
Drop by teaspoonfuls onto ungreased cookie sheets. Press a pecan half into the center of each cookie.
Bake at 350 degrees F. for 7 minutes. (Do not overbake.) Remove cookies to wire racks to cool
Yield: 5 dozen (1 per serving)Recipe submitted by Joyce on 6/1/00