Melt on med-low heat the first 3 ingredients until well blended. Remove from burner, mix 3 1/2 cups powdered sugar (1 cup at a time) until smooth. Spread in 8"x 8" or 9" x 9" pan lined with wax paper. Chill 4 hours. Remove from pan and cut in squares. The first time I tried these was a few years ago, when my daughter in-law brought some to our home during the holidays. I love these! They are delicious! Enjoy!