Heat oven to 350 degrees F. Grease and flour twelve 3-inch oversize muffin-pan cups. Mix flour, cinnamon, baking soda, baking powder, nutmeg, salt and allspice in a bowl.
Beat sugar, oil, and eggs in second bowl. Stir in carrots, then flour mixture just until combined. Stir in chopped nuts and raisins. Spoon about scant 1/2 cup batter into each muffin cup.
Bake in 350 degree F oven 25 minutes or until toothpick tests clean. Cool in pan 5 minutes. Unmold; cool on rack.
Beat butter, cream cheese and vanilla in bowl until well blended. Gradually beat in sugar until creamy.
Spread each cupcake with scant 1/3 cup frosting. Decorate with walnut halves, if desired. Makes 12 oversize cupcakes.
