Crush the berries lightly with the sugar in a small saucepan, using a potato masher. Add water, salt and lemon juice. Simmer until ‘jammy’, it will leave a ‘path’ on the bottom of the pot when stirred (see pic).
Remove the raisin bag from the foil packet and pour boiling water over the raisins to plump them up. Drain immediately and set aside to swell. Adjust oven rack to the middle position. Preheat oven to 190 °C. Grease 2 muffin pans. Beat eggs and oil for 30 seconds on high speed until well blended. Add yoghurt and milk and beat until blended.
Add contents of pack, drained plumped raisins, whole blueberries and blueberry jam. Stir by hand with a wooden spoon ± 40 times until uniformly blended. (Do not beat). Spoon mixture into buttered muffin pan/s. An ice cream scoop does the job perfectly. Bake for about 30 - 35 minutes. Serve with butter.