I just talked with Shirley and here is her recipe for Partridgeberry Jam.

Moy dear, make it loik anyudder, juss use Par'ridgeberries. Add more er less sugar da way you loiks it, roit, see?

So, that is her recipe.... Dere it is by'. Troy dat an see if it's nare da shockin best good ting on eart! Tis.