Step 1: Prepare your ‘sand’. Finely crush vanilla wafers or graham crackers using a food processor or by hand. Place about 1-2 tablespoons of crushed cookies into the bottom of each clear cup. Set aside.
Step 2: In a medium saucepan, bring 1 cup of water to a boil. Remove from heat. Sprinkle the 2 packages of unflavored gelatin over 1/2 cup of cold water in a bowl and let it ‘bloom’ for 5 minutes.
Step 3: Add the bloomed gelatin to the hot water in the saucepan, stirring constantly until completely dissolved (about 2-3 minutes). Ensure there are no granules.
Step 4: Stir in blue food coloring until you achieve your desired shade of ocean blue. If using, add 1/2 cup clear blue drink mix powder and stir until dissolved. Then, stir in the remaining 1 cup of cold water. Allow the mixture to cool slightly.
Step 5: Carefully pour a small layer of blue jello mixture (about 1/4 to 1/2 inch) over the crushed cookie ‘sand’ in each cup. Place a few gummy fish or other sea creatures directly onto this wet jello layer.
Step 6: Transfer the cups to the refrigerator and chill for about 15-20 minutes, or until this first layer is just set but still slightly sticky. This helps to anchor the gummies.
Step 7: Once the first layer is firm, pour another layer of the blue jello mixture into each cup, filling it about halfway. Strategically place more gummy candies within this layer, some against the sides of the cup for better visibility. Return the cups to the refrigerator for another 15-20 minutes until this layer is firm.
Step 8: For the final layer, pour the remaining jello mixture to fill the cups almost to the brim. Add a final scattering of gummy creatures, pushing some just below the surface to create depth.
Step 9: Place the finished Edible Aquarium Jello Cups back into the refrigerator and chill for at least 2-4 hours, or preferably overnight, until completely firm. Serve and enjoy your magical edible aquariums!