Start by bringing 4 cups of water to a boil in a medium saucepan. Once boiling, add the tapioca pearls and stir gently to prevent sticking. Reduce the heat to medium and let them simmer for about 15-20 minutes or until the pearls become translucent, stirring occasionally.
Once cooked, drain the tapioca pearls in a fine mesh strainer and rinse them under cold water to stop the cooking process. This also helps remove excess starch.
In the same saucepan, combine 2 cups of canned coconut milk, 1/2 cup + 2 tablespoons of coconut cream, and 1/2 cup + 2 tablespoons of granulated sweetener. Whisk the mixture over medium heat until the sweetener dissolves completely.
Once the coconut mixture is warm, add the drained tapioca pearls and 1 teaspoon of vanilla extract. Stir well to ensure the pearls are evenly coated. Allow the mixture to simmer on low heat for an additional 5-10 minutes until it thickens slightly.
Remove from heat and let the sago pudding cool for a few minutes before transferring it to serving bowls. Cover and refrigerate for at least 2 hours to let it set properly.
Before serving, blend 1 cup of mango until smooth. Serve the chilled sago pudding topped with a generous dollop of mango puree for a burst of flavor.