Irish creme microwave fudge recipe in the fudge category

: Line an 8 inch square pan with foil, extending foil over the edges of the pan. Butter foil. Set pan aside. Prick potato 2 or 3 times with a fork. Microwave on high for 4 to 5 minutes, turning once. Cool and peel. Mash potato. You should have 1/3 cup. Stir in liqueur and mix until smooth. Set aside. In a 2 quart microwave safe dish, cook chocolate and butter on high for 1 to 2 minutes or until almost melted, stirring once. Stir until smooth. Mix in potato mixture. Slowly add confectioners sugar. Stir or knead until smooth. Press into pan. Score into thirty six 1 1/4 inch squares. Press one walnut half into each square. Chill. Remove from pan. Cut into squares. Drizzle with icing. Designer icing: In small microwave safe bowl, cook butter on high for 45 to 60 seconds or until melted. Beat in confectioners sugar and enough Irish creme liqueur to make of piping or drizzling consistency.