Bloom the gelatin for the panna cotta: In a small bowl, sprinkle the gelatin over 2 tablespoons of cold water. Let stand 5–10 minutes until spongy.
Warm the coconut base: In a saucepan, combine coconut milk, heavy cream, sugar, vanilla, and a pinch of salt.
Heat over medium, stirring, until the sugar dissolves and the mixture is hot but not boiling.
Dissolve the gelatin: Remove the pan from heat. Stir in the bloomed gelatin until fully melted and smooth.
Strain and pour: For a silky texture, strain the mixture through a fine mesh sieve into a measuring cup with a spout. Pour into 6–8 small glasses, filling each halfway.
Chill the first layer: Refrigerate 45–60 minutes, or until set but still slightly jiggly in the center.
It should be firm enough to support the next layer.
Make the mango layer: Bloom the second portion of gelatin in 1 tablespoon cold water for 5–10 minutes. Warm half the mango puree with sugar (or honey) over low heat until the sugar dissolves and the mixture is warm, not hot.
Combine: Remove from heat, stir in the bloomed gelatin until dissolved, then whisk in the remaining mango puree and lime juice. Taste and adjust sweetness or lime.
Add the mango layer: Gently spoon or pour the mango mixture over the set coconut layer.
Tap the glasses lightly to release any bubbles.
Chill to set: Refrigerate at least 2 hours, or until fully set. For best results and easy serving, chill 4 hours or overnight.
Garnish and serve: Top with toasted coconut, lime zest, mint, or diced mango just before serving. Serve cold.