Preheat oven to 350 degrees Fahrenheit. Grease 13" by 9 " or two 9" round metal baking pan(s) depending on whether you want a layer cake or a sheet cake. Line bottom(s) with waxed paper; grease paper. Dust pan(s) with flour.
In medium bowl, combine flour, baking soda, cinnamon, baking powder, salt, and nutmeg.
In large bowl, with mixer at medium-high speed, beat eggs until blended. Gradually add granulated sugar, then brown sugar; beat 2 minutes, frequently scraping bowl with rubber spatula. beat in oil and vanilla. Reduce speed to low; add flour mixture and beat about 1 minute, until smooth, frequently scraping bowl.
Fold in carrots, walnuts, raisins, and pineapple with its juice.
Pour batter into pan. Bake 55 to 60 minutes, until toothpick inserted in center of cake comes out clean, with a few moist crumbs attached. Cool cake in pan on wire rack 10 minutes. Invert cake onto rack and remove waxed paper. Cool cake completely on rack.
In large bowl, with mixer at low speed, beat confectioners' sugar, cream cheese, butter, and vanilla extract just until blended. Increase speed to medium. Beat 1 minute, or until smooth and fluffy, frequently scraping bowl. Makes about 2 1/2 cups.
If you decide to make a sheet cake and frost in the pan you will only need about 2/3 of the frosting recipe.