Have all the ingredients at room temperature.
Position a rack in the lower third of an oven and preheat oven to 325° F.
Generously grease and flour the wells of The Great Pumpkin Pan; tap out the excess flour.
To make the cake:
Over a sheet of waxed paper, sift together the flour, baking powder, baking soda, salt, cinnamon, ginger, nutmeg, allspice and cloves; set aside.
In the bowl of an electric mixer fitted with the flat beater,
beat the butter on medium speed until creamy and smooth, 1 to 2 minutes.
Add the brown and granulated sugars and beat until light and fluffy, about 5 minutes, stopping the mixer occasionally to scrape down the sides of the bowl. Add the eggs, one at a time, beating well after each addition.
Reduce the speed to low and add the flour mixture in three additions, alternating with the milk and beginning and ending with the flour. Beat each addition until just incorporated, stopping the mixer occasionally to scrape down the sides of the bowl. Add the pumpkin puree and beat until incorporated. Remove the bowl from the mixer.
Using a rubber spatula fold in the walnuts and candied ginger until incorporated.
Divide the batter between the wells of the prepared pan and spread it evenly.
Bake until a toothpick inserted near the center of the cake half comes out clean, about 1 hour and 15 minutes.
Transfer the pan to a wire rack and let the cake halves cool upright in the pan for 15 minutes.
Gently tap the pan on a work surface to loosen the cake halves.
Invert the pan onto the rack and lift off the pan.
Let the cake halves cool completely before decorating.
To make frosting:
In the bowl of an electric mixer fitted with the flat beater, beat cream cheese on medium speed until smooth, 2 to 3 minutes. Add the butter and beat until combined, 1 to 2 minutes.
Add the confectioners' sugar and vanilla and beat until fluffy, 2 to 3 minutes.
Divide the frosting between two small bowls and stir the pumpkin puree into one bowl.
Reserve the remaining frosting for decorating.
Using a bread knife, cut 1/4-inch off the flat side of each cake half.
Place one cake half, flat side up, on a cake stand or plate and spread the pumpkin frosting on top.
Place the other cake half, flat side down, on top. Refrigerate for 30 minutes.
Add food coloring as desired to the reserved frosting (green for leaves and tendrils, orange for a jack-o-lantern.
To create leaves and tendrils:
Using a rubber spatula, transfer the green frosting to a pastry bag fitted with a leaf or medium plain tip. Pipe leaves and tendrils on the top of the cake.
To create a jack-o-lantern:
using a rubber spatula, transfer the orange frosting to a pastry bag fitted with a medium plain tip.
Pipe an outline of the face on the cake, then fill in the design.