Mix lemon juice, rind, rapadura, salt and whey. Combine with chopped fruit.Stir in optional nuts, raisins, and spices, and place in a wide mouth quart mason jar. Press down lightly, adding more whey (I’ve also added some fresh juice from the fruit, too) to cover the fruit. Mixture should come to 1 inch below the top of the jar.Cover tightly, and keep at room temperature for 2 days, then transfer to fridge. Use within 2 months.Omit nuts and after fruit is ready for transfer to fridge, puree until smooth. Store in the fridge with a little whey or lemon juice poured over the surface to prevent discoloration. I usually make my chutney that hasn't been eaten right away into this jam, as the lactic acid continues to break down the fruit over time, changing the texture.