I used 300 g of Physalis; 200 g of Demerara Sugar, and the juice of 1 1/2 limes to make the jam. I prepared the fruit by easing them with salt and water and cutting them into quarters.
Mix the sugar and lime juice in a cup of water and bring this mixture to boil in a thick bottomed pan on high heat. Once the sugar has completely dissolved and the mixture is bubbling, add the chopped physalis to the pan. Wait till the mixture comes to a boil again and then lower the heat so that the mixture in the pan is simmering.
I tested it to see if it was done after about 30 minutes.
How to test if a jam is done?
- Place a few drops of the jam on a cold spoon and put the spoon in the fridge for a couple of minutes.
- Take the spoon out and push at the jam with a finger; if it wrinkles, it is done.
If not, continue to simmer till it is done; checking at 5 minute intervals. My jam was done in about 45 minutes.