Cut the limes in half, then squeeze out the juice. Use a knife to then scrape out the pulp, taking care not to cut the flesh. This is quite fiddly and will take time but the cleaner your limes, the better the finished result.
Take 2 mini-muffin tins and set the lime halves empty side up into each muffin hole.
Add the boiling water to the jelly and stir for 2 minutes until fully dissolved. Pour mixture into lime halves, filling all the way to the top.
Chill the jelly limes in the fridge for at least two hours.
When set, turn the jelly-limes onto a cutting board and using a sharp knife, cut each lime in half again to make a wedge.