1) Prick the each plum with toothpicks in 2 or 3 times.
2) In a slow cooker, place the plums.
3) Stream in the water to cover the plums by half.
4) Stir in the spices and lemon rind.
5) Put the lid on and simmer for 3 to 4 hours until tender.
6) Stir in the sugar until melted.
7) Remove from heat and discard the spices.
8) Serve warm or cold with a dollop of sour cream.