Photo: Erik Putz
Cake
1. Use box mixes to bake three cake layers in three circular pans: one 9-in., one 8-in. and one 6-in. Cut a 2-in. circle in the centre of each of them, then stack from largest to smallest, spreading

blue icing between the layers. Insert skewers to hold the cake in place, and trim the ends of the skewers so they don?t poke out.
2. Using a serrated knife, trim the edges of the cakes to create a rounded dome shape. Add a crumb coat of blue icing around entire cake, and refrigerate until icing is firm, about 15 min. Place a doll in the centre hole (the top of the cake should reach the doll?s torso). Spread another layer of blue icing for waves.
3. Draw the shape of a mermaid tail on the icing with a toothpick. Starting from the bottom, fill in the shape with M&Ms, overlapping the candies slightly to resemble scales. Decorate the rest of the cake, adding brown sugar for sand and edible chocolate seashells. Use leaf-shaped gummi candies for the tail fins.
Illustrations: Flo Leung
Decor
Tape green streamers (seaweed) to the top of a wall and twist; secure ends at the bottom. Add a few marine friends to your seascape with paper cut-outs of fish and sea horses. Above your food table, pin a big net (find one at a craft store or hardware store), and fill it with purple and turquoise balloons. Layer two or three inexpensive plastic tablecloths in shades of blue and green, and then use scissors to give the tablecloths scalloped edges at...