Lettuce Soup

|Sounds crazy but avoids waste! Any kind of potato and any salad greens including lettuce rocket spinach and watercress will work fine.|butter lettuce cress gem lettuce lettuce potatoes rocket shallots spinach watercress|55g onions or scallions or shallots chopped1 clove garlic chopped45g butter unsalted¾ teaspoon salt¾ teaspoon ground coriander¼ teaspoon pepper105g potato peeled and diced120g lettuce leaves including ribs coarsely chopped700ml water|Cook onion mixture and garlic in 30g butter in a large heavy pot over moderately low heat stirring until softened 3 to 5 minutes. Add coriander salt and pepper and cook stirring 1 minute. Stir in potato lettuce and water and bring to a boil then reduce heat and simmer covered until potato is very tender about 10 minutes.Turn off the heat. Use an immersion blender to purée soup right in the pot or do it in batches in a blender (use caution when blending hot liquids). Bring the soup back to a simmer then whisk in remaining tablespoon butter and salt and pepper to taste.|10.00 minutes|4|Epicurious