For 1 person
Place the ground cherries in a pot.
Add the lemon juice and cook over low heat until the ground cherries open and release their juice.
Add the sugar and cook over medium heat until the jam thickens (about 15 minutes).
Pour the jam into one or more Mason jars, leaving 1/4 inch of headspace.
Store the jam in the refrigerator or seal it in a boiling water bath for 5 minutes.