1/2 lbs potatoes, peeled
1/2 c milk
2 c flour
2 tsp baking powder
1/2 tsp salt
1 c shortening
2 c sugar
4 eggs
1 tsp vanilla
1 1/2 oz unsweetened chocolate, melted 

Cook potatoes in small amount of boiling water in covered saucepan until tender. Drain well. Shake pan over low heat to dry contents thoroughly. Force hot potatoes through ricer or sieve. Combine 1 cup sieved potatoes with milk; set aside to cool. Sift flour, baking powder and salt together. Cream shortening; beat in sugar gradually until light and fluffy. Add eggs, one at a time, beating well after each addition. Mix in vanilla and chocolate. Add dry ingredients in 4 parts and potato mixture in 3. {Alternate to cream mixture.} Beat only until smooth after each addition. Bake in preheated 350 degree oven in a 13x9 inch pan for 45 minutes, or until cake tests done. Remove and let stand 10 minutes.