Preheat your oven to 350 degrees Fahrenheit. Then, be sure to dust, line, and grease your 9-inch round cake pans (3 pieces).
Afterward, mix your butter and sugar in a large mixing bowl. Next, beat for five to seven minutes or until light and fluffy. After that, add your eggs a single at a time. With that, be sure to beat after each addition. Also, place your flour, baking powder, salt, and baking soda in a separate bowl. Then, alternately add butter and sour cream, whisking after each addition.
1 cup butter, softened, 2 1/2 cups sugar, 4 large eggs, room temperature, 1 tsp salt, 4 cups all-purpose flour, 3 tsp baking powder, 1/2 tsp baking soda, 1-1/2 cups sour cream
Next, divide your cake batter into three cake pans. After that, bake your cake for about twenty-five to thirty minutes. Likewise, you can do so until cooked thoroughly. Also, make sure to cool your cakes for about ten minutes inside the pan before removing them from the cooling wire rack.
Melt baking chips in the microwave with cream stirring every 30 seconds until smooth. Stir in your vanilla. Set aside to cool. Using a heatproof bowl, whisk egg whites, sugar, salt, and cream of tartar until combined. Over simmering water, place the heatproof bowl over medium heat. Whisk the mixture constantly for about 8 to 10 minutes or until the thermometer reads 160 degrees.
6 ounces of white baking chips, 2 tsp vanilla extract, 6 large egg whites, room temperature, 1 1/2 cups sugar, 1/2 tsp cream of tartar, 1/2 tsp salt, 1/4 cup heavy whipping cream
Then, remove the heatproof bowl from heat, and using an electric mixer, beat the mixture at high speed for about seven minutes until it cools down to 90 degrees. Also, slowly beat a few tablespoons of butter at medium speed. Remember to do so until it becomes smooth. Besides that, beat in cooled baking chips mixture until well combined.
2 cups unsalted butter, cubed
After that, reserve 1/4 cup of frosting. Also, make sure to color the remaining frosting with your desired shades of blue. In addition to that, be sure to fill and frost your cakes using blue frosting. Color 1/2 ounce of fondant with red and one portion of blue. Leave the other half white. Then, dust the work surface using powdered sugar and roll out your blue fondant to 1/8-inches in thickness.
Blue, red, and green liquid food coloring
Afterward, make sure to cut out one circle in the fondant using a three-inch round cutter. With this, repeat the process using white fondant. Also, using a craft knife, create the mouth opening, teeth, and body shape on the lower portion of your white circle. Then, place the white fondant cut out on the blue circle.
4 ounces ready-to-use rolled fondant
Roll out your red fondant into a 1/8-inch thick. Then, make sure to cut a small triangle. And place it in the mouth opening under the white fondant. Also, you may brush the fondant with water or glue to help the layers stick. Afterward, cut a crescent moon shape using the remaining rolled blue fondant to create the shark's tail and fin.
Stick the fin and tail into your shark's body. Then, be sure to brush the edges lightly with water if required to secure them together. Besides that, ensure to stick the candy eyes into the shark's body using a tiny amount of reserved frosting.
2 candy eyes
Finally, position the fondant shark on the side of the cake. Then, make sure to press the fondant shark gently into the cake. Also, color the remaining reserved frosting green and use a leaf tip to pipe seaweed on the sides of the cake. As always, be sure to serve and enjoy!