Prep the mango: Peel and cube the mango.
Blend until very smooth. You should have about 2 cups of puree. If you want an ultra-smooth pudding, strain the puree through a fine-mesh sieve.
Bloom the gelatin: Sprinkle the gelatin over 3 tablespoons of cold water in a small bowl.
Let it sit for 5 minutes until it swells and looks spongy.
Warm the dairy: In a small saucepan, combine milk and cream (if using). Add the sweetener and a pinch of salt. Warm over low heat, stirring, until the sweetener dissolves and the mixture is hot but not boiling.
Melt the gelatin: Remove the warm milk from the heat.
Add the bloomed gelatin and stir until fully dissolved. If any grains remain, return to low heat briefly, stirring constantly.
Combine with mango: In a mixing bowl, whisk together the mango puree, lime juice, and vanilla. Slowly whisk in the warm milk-gelatin mixture until smooth and even.
Taste and adjust: Taste the mixture.
Add a little more sweetener if needed. Remember it will taste slightly less sweet once chilled.
Chill to set: Pour into 4 to 6 small ramekins or glasses. Cover and refrigerate at least 4 hours, or until the pudding jiggles softly and holds its shape.
Garnish and serve: Top with diced mango, toasted coconut, chopped pistachios, or mint.
Serve cold.