Preheat oven to 350°F. Grease and flour 13 x 9-inch non stick baking pan or spray with baking spray; set aside.
Spread pecans in an even layer on a baking sheet. Toast in the preheated oven for 6-8 minutes. Set aside to cool.
Cake: In a medium-size bowl, use a whisk to sift together flour, cinnamon, baking soda, salt, allspice, ginger and nutmeg.
In a separate bowl, use an electric mixer to beat together melted butter, brown sugar, granulated sugar, sour cream, eggs and vanilla. Beat at medium speed, scraping bowl periodically, until creamy.
Lower speed of mixer and gradually add dry ingredients. Beat just until fully combined. Mix in carrots, pineapple, coconut and 1/2 cup toasted nuts by hand until evenly distributed.
Pour batter evenly into prepared pan. Bake for 30-40 minutes or until a toothpick inserted into the center comes back clean. Cool completely in the pan on a cooling rack.
Cream Cheese Frosting: In a medium-size mixing bowl, use an electric mixer to cream together cream cheese and butter. Add 4 cups powdered sugar and reserved pineapple juice. Beat until fluffy and smooth adding additional powdered sugar in rounded tablespoons if needed, until spreading consistency is reached. (This amount may vary depending on the amount of juice)
Frost top of carrot cake and sprinkle with reserved toasted pecans.
Cover and chill for at least 4 hours. Cut into squares and serve.
Store leftovers chilled in an airtight container for up to one week.