Preheat oven to 350 degrees F. Butter and flour two 9"x13" cake pans.

Prepared cake mix according to package directions, adding pineapple extract after batter is mixed together.

Pour cake batter into prepared pans, and back according to package directions. Remove cakes from oven and cool completely.

In a large bowl, beat together butter, powered sugar, and pineapple juice until smooth and fluffy. Add milk (1 tablespoon at a time) if frosting is too dry. Add powdered sugar (1 to 2 tablespoons at a time) if frosting is too wet.

Place 1/3 of the frosting in a separate bowl, and add the pineapple chunks to this frosting. Stir to combine.

To the remaining 2/3 of the frosting add 2 parts electric blue food coloring to 1 part turquoise food coloring for a bright ocean blue color. I did 6 drops blue to 3 drops turquoise - adjust the colors as needed to your liking. Be sure to thoroughly stir the food coloring into frosting before adjusting colors.

Melt candy melts according to package directions. Fill seashell molds with melted candy. Be sure to scraper the top of the mold to remove excess candy so the seashells have a flat back. Place mold in fridge while you assemble to cake, until the candy is set.

Once cakes are cooled, take a serrated knife or cake saw and even out the layers. Place one layer on the cake board, and top with the pineapple chunk frosting. Spread evenly over the cake layer. Top filling with the other cake layer, putting the layer bottom side up. Frosting the entire cake with the blue frosting.

choose one side of the cake to be the "beach" and sprinkle your graham crackers crumbs over that side and around the corners a bit to make the "sand." Top cake with luau themed cake toppers and candy seashells.

Place 2 flowers in the top opposite corner of the cake from the beach. Place 2 flowers in the bottom corner of the cake below the beach (as pictured). Use the ocean as your space to write any message you're putting on the cake. Refrigerate if not serving within 30 minutes of finishing the cake.