Cube the mangoes and put it, together with the seeds, in a bowl.

Add the sugar and lime juice. Mix and refrigerate for 3 hours.

Then, cook, stirring, for about 20 to 30 minutes or until thick.

After 15 minutes, add the vanilla extract.

While the jam is cooking, put a small plate in the freezer.

After 20 minutes, when the jam appears like it is beginning to gel, put the fire off.

Put a small amount of jam on the frozen plate and return it to the freezer for a few minutes. If it wrinkles when you nudge it, it’s ready. If not, cook it some more and test it again until it’s ready.

Blend the jam with a hand blender and store it in sterilised jars.