Stir together the milk in a saucepan with half of the mango puree to start with and place over a medium heat. (Using only half the puree first stops the milk from catching.)
Meanwhile, in a separate heatproof bowl, whisk the egg yolks with the rest of the mango puree to combine.
When the milk is steaming hot and just about to come to the boil (do not let it boil), slowly pour roughly two thirds of it over the yolks, whisking vigorously as you pour, until smooth and combined.
Pour the yolk mix back into the pan over low heat with the remaining milk and whisk well to incorporate.
Get rid of your whisk and switch to a spatula. Basically you're now aiming to gently bring it to 82°C/180°F, no biggie. Just keep the heat low and gently stir with your spatula for about 5-7 minutes/ Once the bubbles start to disappear, you're nearly there. Remember, you have control over this, so take it off the heat and stir for a bit if you need.
When the custard is thick enough to coat the back of a spoon it's ready.
Soak the gelatin in a little ice-cold water.
Squeeze out the gelatin and stir into the warm anglaise along with the lime juice. Set aside for a moment.