Prep the Molds: Arrange your chosen fresh diced fruit evenly across the bottoms of your silicone molds or ice cube trays.
Whisk & Dissolve: In a small saucepan, whisk the agar-agar powder into the cold fruit juice until completely dissolved.
Activate the Gel: Place the saucepan over medium heat and bring the mixture to a full boil. Crucial Step: Allow it to simmer rapidly for 1 to 2 minutes while whisking constantly. Agar-agar must reach a boil to activate its gelling properties.
Pour & Set: Remove from heat and carefully pour the hot juice mixture over the fruit in your molds.
Chill: Let the molds rest at room temperature for 10 minutes, then transfer to the refrigerator for 20 to 30 minutes until fully firm. Pop them out of the molds and serve!