Spot prawns are available fresh at farmers markets and sustainable-fish stores for the next few weeks or frozen all year. If desired, use medium shrimp instead.
2 tbsp butter
2 cups sliced leeks, dark green leaves removed
1 cup peeled, diced yellow-flesh potato
4 cups chicken stock
4 bunches sorrel, enough to make 4 packed cups
¼ cup whipping cream
2 tsp lemon juice
Salt and freshly ground pepper
18 spot prawns or medium tiger shrimp
2 tbsp chopped chives
Heat butter in a soup pot over medium. Add leeks and potato and sauté for 5 minutes or until slightly softened. Pour in the stock and bring to a boil. Reduce heat and simmer for 10 to 15 minutes or until the potatoes are tender.
Stir in 3 cups sorrel and simmer for 2 minutes or until the sorrel has wilted. Use a hand blender or a food processor to blend it until smooth. Return pot to heat and add cream and lemon juice.
Bring to a boil then simmer for 5 minutes. Add the remaining sorrel for the last minute of cooking. Season to taste. Bring a medium pot of water to a boil. Place spot prawns in a large bowl. Pour boiling water over prawns and let sit for 5 minutes. Drain immediately. Peel, season with salt and pepper and toss with 1 tablespoon of chives.
Spoon soup into 6 bowls. Top with prawns and sprinkle with the remaining chives.