Pour 1/2 cup of the water into a large mixing bowl, and sprinkle the gelatin powder over the top to bloom. Let it sit for 10 minutes.
Add the mango, sugar, cream, and milk to a blender. Process on medium low speed until smooth, and strain through a fine mesh strainer into a bowl. Use a spatula to push the mixture through the strainer as needed. Discard any leftover pulp.
In a small saucepan (or in the microwave), heat your remaining water until boiling, and pour it over the bloomed gelatin. Mix until gelatin is fully dissolved.
Add the mango to the gelatin mixture, and stir till everything is combined.
Pour your mixture into a wide and shallow container. Remember that the depth to which you pour will be how tall your jellies are - I like to make it no deeper than 1/4 inch for adding to drinks (so they can pass through a bubble tea straws). I use small rimmed baking sheets.
Cover and refrigerate at least 12 hours.
Cut the puddings to 1/4 inch dice (or to your preferred size) before serving. Store in an airtight container, refrigerated, up to 1 week.