2 1/4 cups brown sugar
1/2 cup milk
3/4 cup peanut butter
1 teaspoon vanilla extract
3 1/2 cups confectioners' sugar
Melt butter in a medium saucepan over medium heat. Stir in brown sugar and milk. Bring to a boil and boil for 2 minutes, stirring frequently. Remove from heat. Stir in peanut butter and vanilla. Pour over confectioners' sugar in a large mixing bowl. Beat until smooth; pour into an 8x8 inch dish. Chill until firm and cut into squares.