1 cup of white chocolate chips and a candy mold for shells (optional)
2 boxes cake mix or equivalent cake recipe (I recommend Organics brand, which can be found at natural foods stores).
Frosting for two cakes
1 box of wafer cookies (I used a box of Trader Joe's toasted coconut cookie thins plus 2 handfulls of animal crackers, but vanilla wafers or graham crackers are fine too.)
2 to 4 sugar ice cream cones
2 to 4 cake ice cream cones
sprinkles or other decorations (plastic mermaids, fish, Swedish fish, would all be fun)
Instructions
Make white chocolate shells early so you have one less thing to worry about. Melt chips in a microwave safe bowl at 20 second intervals, stirring between the intervals, until chips have melted. Cool slightly and then pour into a pastry bag or plastic zipper bag. Snip off the tip and carefully pipe the white chocolate into the candy mold. Tap the mold on the counter repeatedly to release air bubbles. You will see little bubbles come to the surface. Place in the refrigerator to harden. Store in the refrigerator until ready to use. I piped a sea fan shape onto a piece of wax paper as well.
Make cake batter according to recipe instructions and preheat the oven to specified temperature. Butter and lightly flour your cake pans. Pour batter into the prepared pans/dishes and smooth with a spatula. Bake according to recipe directions, but note that smaller baking dishes may cook more quickly and should be checked on frequently. Remove from oven when a toothpick inserted comes out clean. Cool on a cooling rack and remove cakes from pans. If making early and freezing, cool completely, wrap in plastic wrap and then again in foil and freeze. Otherwise you can leave cakes unfrosted and uncut for a day or two.
Prepare frosting according to package directions. Cut any domes on the cakes off with a serrated knife so that the tops and bottoms are flat. With an offset spatula, frost the bottom layer of cake. Add the next layer and frost. Continue frosting and building your cake. Sometimes it's frosting goes on my smoothly after chilling the cake in the freezer for a few minutes.
Place cookies in the bowl of a food processor. If your frosting is very wet you should wait until party day to add the crumbs so that they don't get mushy. My frosting was quickly forming a "crust" so I added the crumbs right after frosting the cake. Pulse until all the cookies are finely ground. Gently press the crumbs into the frosting.
If making the flag towers, carefully cut 1/2" off the tips of sugar cones. Insert the wide end of the sugar cones into the tops of the cake cones with cake cones standing right in front of the cake. Insert flags into sugar cone holes. Add any decorations such as sprinkles, toy mermaids or fish, treasure, or white chocolate shells.