Combine the mango puree and sugar in a medium heatproof bowl. Add the lime juice and a pinch of fine salt to taste.
Once you're happy with the flavour, add the eggs and whisk to combine.
Melt the coconut oil using your preferred method, being careful not to burn it (it takes on a flavour once burnt). Allow it to cool a little before adding it to the curd mixture.
Place the heatproof bowl on a small sauce filled 1/3 with water. Make sure the bowl doesn't touch the water. Cook the curd on the smallest hob at a medium heat for 10-15 minutes, stirring very regularly. I like to use a silicon spatula to ensure that I am moving the curd around efficiently. This prevents any patches from over-cooking.
The curd should have lightened just a little in colour and become tangibly thicker. It will thicken further in the fridge, but it should easily coat a spoon and form small track lines in the surface as you stir.
Take the curd off the heat. As a precaution, you can place the bowl in an ice bath to stop the cooking time and speed up cooling.
After about 15 minutes, cover the surface of the curd with cling film and place in the fridge to cool and set. I like to make this curd the night before I need it so it is lovely and thick and ready to go.
Curd keeps well in the fridge for a number of days and can be frozen and defrosted.