Heat oven to 350 degrees. Grease an 8x8 pan.
Measure potato flakes into the mixing bowl. Blend in hot water; set aside.
Melt shortening and chocolate over low heat, stirring constantly. Add chocolate mixture, sugar and eggs to potatoes in the bowl.
Stir together remaining ingredients; blend into chocolate mixture. Pour into prepared pan. Bake 25 to 30 minutes. Cool; if desired, frost.