Heat oven to 350°F. Line a jumbo cupcake pan with 6 foil or paper liners.
In a bowl, whisk flour, baking powder, baking soda, allspice, ginger, salt.
In a large bowl, beat together maple syrup and half the milk. Beat in flour mixture and shortening until blended; 4 minutes. Beat in eggs and remaining milk until smooth. Stir in carrots and pineapple.
Divide batter evenly among prepared cupcake liners, 2/3 cup batter in each. Bake at 350°F for 28 minutes, or until lightly browned. Remove from pan; cool on rack.
In a medium-size bowl, beat together cream cheese and butter. Beat in sugar until smooth. Place 2/3 cup frosting in a bowl; tint with food coloring. Transfer to a pastry bag fitted with a small round tip. Spread white frosting over cakes. Pipe a spiral on top of cakes with tinted icing. Starting in center, draw a knife outward through spiral to create a spider-web.