1. Heat oven to 350 degrees F. Coat bottoms of three 8 x 2-inch round cake pans with nonstick cooking spray. Line bottom of pans with parchment or wax paper; coat with spray.
2. In a medium-size bowl, whisk together flour, baking soda, pumpkin pie spice, cinnamon and salt. In a large bowl, beat sugar, oil, eggs and 1 1/2 teaspoons of the vanilla until blended. On low speed, gradually beat in flour mixture until smooth. Stir in carrots, pineapple with its juice, nuts and raisins. Divide batter among prepared pans, about 2 generous cups in each. Spread evenly.
3. Place two of the pans on the middle rack of the oven and the third pan in the middle of the top rack. Bake at 350 degrees F for 40 minutes or until toothpick inserted in centers of cake layers comes out clean. Cool in pans on wire rack for 10 minutes. Turn out onto wire racks, removing pans and paper. Cool completely.
4. In a large bowl, beat cream cheese, butter and remaining teaspoon vanilla until light and creamy, about 2 minutes. On low speed, gradually beat in confectioners' sugar. Beat until fluffy, about 2 minutes.
5. With a serrated knife, trim tops of layers to make level. Place one layer on serving plate. Spread 3/4 cup frosting over top. Repeat with second layer. Place third layer on top and spread with 1 cup frosting; spread remaining frosting around side of cake. Garnish with chopped nuts around top edge of cake, if desired. Refrigerate cake for at least 1 hour, or until frosting is set.