In a large mixing bowl, combine the first eight ingredients. Add eggs, oil, potatoes and extract; beat until combined. Stir in the pineapple, raisins and walnuts. Fill 12 greased or paper-lined jumbo muffin cups three-fourths full.
Bake at 350 degrees for 25–30 minutes or until a toothpick comes out clean. Cool for 10 minutes before removing from pans to wire racks to cool completely.
For frosting, in a large mixing bowl, beat cream cheese and butter until fluffy. Beat in the sugars and extracts until smooth. Frost sides of cakes; roll in walnuts. Place cakes upside down and frost tops with remaining frosting.