Spray 6 - 1/2 cup molds with cooking spray. Set aside.
In a small saucepan add the coconut water, sugar and gelatin. Bring to a simmer over medium-low heat and stir until the gelatin has dissolved. Divide between the 6 molds and set on a small baking sheet.
Chill for 3-4 hours or until firm.
Blackberry Juice Layer
In a small saucepan add the blackberries and 1/2 cup of cold water. Bring to a boil over medium-high heat. Cook berries for 10-15 minutes, breaking them up with the back of a spoon.
Set a fine meshed sieve over a medium bowl and push the berry juice through using a rubber spatula. Continue to push the juice through the sieve until all that remains is pulp and seeds and discard.
In a small saucepan add 1/2 cup blackberry juice, 1/2 cup sugar , remaining 1/2 cup water and gelatin. Bring to a simmer over medium-low heat and stir until the gelatin has dissolved. Remove from heat and allow to cool for 10 minutes.
Remove the molds from the refrigerator and carefully ladle the blackberry juice over the coconut water layer. Return to the refrigerator and chill for 2-3 hours longer.
Remove from the refrigerator and place a serving plate over the mold and invert. If the gelatin is sticking, you can use the water-bath method mentioned above.
Serve with fresh blackberries and fresh whipped cream if desired.
Notes
Tips for Storing
Keep the gelatin covered in the refrigerator and enjoy it within 3 to 4 days for the best texture.
Store it in the molds until you're ready to serve so the layers stay firm and neat.
Press plastic wrap gently over the surface to prevent a rubbery skin from forming.
Do not freeze it. Gelatin turns weepy and grainy once thawed.
If you're making it ahead for a party, unmold just before serving so the shapes stay sharp.