I didn’t want even a hint of a bitter marmalade aftertaste, so rather than add grated zest, I followed the method in Apple-Orange-Cranberry Sauce, where the peel is boiled before being combined with the berries, apple and sugar.
6.5 cups fresh cranberries
3.5 cups fresh raspberries
Juice of 1 Meyer lemon
Rind of 1/2 Meyer lemon
Juice of 1 Valencia orange
Rind of 1/2 Valencia orange
1 Granny Smith apple, peeled
4 cups sugar
3 cups water
Put the cranberries, raspberries and sugar in a large preserving pan and bring to the boil. Lower heat and simmer 3-4 minutes, or until you hear just a few cranberries pop. Turn off the heat and let rest 30 minutes.
Meanwhile, pare all (and really, all) the white pith from the inside of half a lemon and half an orange. Chop the peel into tiny squares and boil in the water for 10 minutes. Drain, discard water, and add peel to berry mixture.
Core the apple and shop into cubes around 1/2 cm wide. Add apple to berry mixture and bring everything to a boil again. Simmer for 2-3 minutes, or until a few more berries pop.
Remove berry mixture to a glass or ceramic bowl. Cover with parchment paper and leave to cool slightly before refrigerating overnight.
The next day, return the berry mixture to the pan and bring to a gentle boil, stirring at regular intervals, until the berries start popping. Mash any unpopped berries into the jam. Cranberries will set quickly without any help so be sure to remove from the heat when the jam passes a light wrinkle test to avoid making an overly stiff jelly.