PUREED MIXED VEGETABLE SOUP

Steps:

• Sweat aromatics Melt butter in a medium stockpot over medium heat. Cook onion and garlic (if using), stirring constantly, until softened and translucent, about 3 minutes.
• Add base vegetables and stock Add potato, broccoli, and carrots along with enough stock (or water) to just cover. Season with salt and pepper and bring to a boil, then reduce heat and simmer 10 minutes. Add spinach and continue cooking until vegetables can easily be mashed with the back of a wooden spoon, about 5 minutes more.
• Puree Reserve 1 cup liquid for thinning soup. Puree the rest of the contents in a blender, food processor, or food mill, working in batches as necessary (do not fill blender or processor more than halfway, and cover the lid with a kitchen towel while machine is running).
• Finish soup Return puree to clean pot, and set over low heat; whisk in cream (or buttermilk), if using, and add enough reserved liquid to thin soup to desired consistency. Season with salt and pepper. Serve immediately, or let cool completely, then refrigerate in a covered container. Reheat over moderate heat, just to warm through, thinning with more liquid as necessary.
• FOLLOW THE BASIC RECIPE, adding 1/2 teaspoon ground cumin and 1/2 teaspoon ground coriander when sweating the aromatics and using 1 pound cauliflower (1 head), trimmed and cut into 1-inch pieces and the same amount of potato for the base vegetables. Proceed with the recipe to simmer and puree. Serves 6.
• TO MAKE THE SOUP, FOLLOW basic recipe to sweat the aromatics, then add 1 can (28 ounces) whole peeled tomatoes or 2 pounds fresh tomatoes, blanched and peeled (page 381), as the base vegetable, and 1 1/2 cups stock or water. Proceed with recipe, simmering tomatoes 10 minutes (they should be soft and beginning to fall apart). Puree and finish with heavy cream, if desired. (serves 4)
• FOLLOW THE BASIC RECIPE, sweating 1 piece (1 inch) fresh ginger, peeled and thinly sliced, along with the onion and 1 small clove garlic. Then add 1 1/2 pounds carrots (8 medium), peeled and cut into 1/2-inch-thick rounds, as the base vegetable, and 4 cups water. Proceed with recipe to simmer and puree. Do not finish with cream or buttermilk. (serves 4)
• FOLLOW THE BASIC RECIPE, sweating 3 medium leeks, white and pale-green parts only cut into 1/2-inch-thick half-moons (2 1/4 cups) and washed well (page 32), for aromatics, then adding 1 1/2 pounds russet potatoes (2 large), peeled and cut into 1-inch chunks (4 cups), for the base vegetable, and 3 1/2 cups stock or water. Proceed with recipe, simmering for about 15 minutes, then remove from heat. Puree, then add 3/4 cup each heavy cream and buttermilk. Thin with water or stock to reach desired consistency. Cool soup completely before refrigerating in an airtight container, up to 3 days; thin with stock or water as necessary before serving. (serves 6)
• FOLLOW THE BASIC RECIPE, omitting garlic and sweating 1 Bosc pear, peeled, cored, and quartered, along with the onion. Then add stock or water and use 1 1/4 pounds winter squash (butternut, acorn, or kabocha), peeled, seeded, and cut into 1-inch chunks, for the base vegetable, and proceed with recipe to simmer until tender and puree. Finish with 1/2 cup buttermilk, if desired. (serves 4 to 6)
• FOLLOW THE BASIC RECIPE to sweat the aromatics, then add 3 1/2 cups stock or water and bring to a boil. For the base vegetables, add 2 pounds fresh green peas, shelled (2 cups), and return to a boil, then reduce to a simmer and cook until bright green and tender, 2 to 3 minutes. Then stir in 1 pound (2 bunches) fresh flat-leaf spinach (in batches if necessary, stirring until each is wilted) and cook until wilted, 2 to 3 minutes. Puree and finish, thinning with water as desired, then season with 2 teaspoons fresh lemon juice along with salt and pepper. (serves 4)