Preheat the oven to 350 degrees F. Coat the inside of a 1-quart ovenproof bowl and a 2-cup ovenproof measuring cup with cooking spray. Prepare the cake mix as the label directs. Pour 2 cups batter into the measuring cup and the rest into the bowl.
Bake the cakes until a toothpick inserted into the centers comes out clean, 35 to 45 minutes. Let cool 15 minutes in the bowl and cup, then invert onto a rack to cool completely.
Make the frosting: Beat the marshmallow cream, butter and confectioners' sugar with a mixer until fluffy, 3 minutes. Tint dark green with green food coloring and a few drops of red. (If the frosting is too thick, beat in 1 tablespoon hot water.)
Flip the cakes right-side up. Trim the top of the bowl cake to make it level. Cut off a 1 1/2-inch piece from the bottom of the cup-shaped cake, then trim the top to make it level. Reserve all the cake trimmings.
Put the bowl cake on a baking sheet, trimmed-side up. Spread the top with a layer of frosting, then place the cup-shaped cake on top, wide-end down. Freeze about 20 minutes.
Melt the green and red candy melts with the shortening in the microwave. Dip the back of 10 plastic spoons in the candy to coat (do not let the candy go over the edge). Place on a separate baking sheet lined with wax paper. Freeze until set, no more than 5 minutes.
Remove from the freezer. Carefully bend the bowl of the spoon and the handle to release the candy shell. (Don't worry if some break-you can remelt them.) Repeat to make about 80 leaves, remelting the candy as needed.
Use a paring knife to trim 1 inch from the narrow end of each candy leaf. Save the small trimmed pieces for the top of the cake. (You can make the leaves a day ahead; store in an airtight container at room temperature.)
Transfer the cake to a serving plate; arrange strips of wax paper around the bottom edge of the cake to keep the plate clean. Cover the cake with a generous layer of frosting to make an artichoke shape.
Starting at the top center of the cake, arrange the small trimmed candy pieces in concentric circles, cut-edge up; cover the entire top. Place rows of the large candy leaves around the side of the cake to cover completely. Chill to set the frosting.
Crumble the reserved cake trimmings on a baking sheet. Bake at 350 degrees F, stirring, until toasted; cool. Place the coconut in a resealable bag with 2 drops green food coloring; massage until green. Empty into a bowl and crumble in the cake crumbs.
Sprinkle the crumb mixture on top of the cake and into the leaves. Refrigerate until ready to serve.
Photograph by Andrew Purcell
Recipe courtesy of Karen Tack and Alan Richardson for Food Network Magazine