Combine agar-agar and water in a bowl.
Allow it to bloom in water for around 5 minutes.
Add chocolate chips to a bowl. Set it aside.
Meanwhile, heat 1 cup of heavy cream in a saucepan over medium-high heat. Bring it to a slight boil.
Add bloomed agar-agar to cream and allow it simmer for about 5 minutes (on medium-low heat) until it is completely dissolved. This process will hydrate agar-agar, which will allow it to set well. After 5 minutes, take it off the flame. The cream will become slightly thick.
Pour this mixture over chocolate chips and whisk until chocolate is completely melted. Set aside to cool to about room temperature. Keep stirring occasionally.
The chocolate mix will become thick. Please do not add hot chocolate to whipped cream.
Combine remaining 2 cups of heavy cream, powdered sugar, and cornstarch to a bowl. Beat until stiff peaks forms. Cornflour/cornstarch helps whipped cream to holds its shape. It acts as a stabilizing agent.
Carefully stir in half of the whipped cream into the melted chocolate-agar-agar-mix.
Fold it gently until fully incorporated. Do not whisk. Tip - Folding will keep all the air bubbles intact for a lighter and airy texture. Repeat the process with rest of the whipped cream and fold gently.