• 4 stalks lemongrass
  
• 2 cans (14 ounces each) unsweetened coconut milk
  
• 1-1/2 cups Vegetable Stock
  
• 20 quarter-sized slices fresh galanga or ginger or 10 large pieces dried galanga
  
• 10 peppercorns
  
• 20 wild lime leaves, or 12 strips lime zest, each about 2 inches long by 1/2 inch wide
  
• 1 butternut squash, about 1-1/2 pounds
  
• 1 can (15 ounces) straw mushrooms, rinsed and drained, or 6 ounces fresh mushrooms, sliced (about 1-1/4 cups)
  
• 8 ounces firm tofu, cut into bite-sized chunks
  
• 1 tablespoon soy sauce
  
• 1 teaspoon salt
  
• 2 tablespoons freshly squeezed lime juice
  
• 1/2 cup coarsely chopped fresh cilantro
  
• 3 green onions, thinly sliced crosswise

Trim the lemon grass stalks: Cut away and discard any hard, dried root portions, leaving a smooth, flat base just below the bulb. Trim away the tops, including any dried, brown leaf portions; you should have handsome stalks about 6 inches long, including the bulbous base. Using the blunt edge of a cleaver blade or heavy knife or the side of an unopened can, bruise each stalk, whacking it firmly at 2-inch intervals and rolling it over to bruise on all sides. Cut into 2-inch lengths.

In a 3-quart saucepan, combine the coconut milk and vegetable stock, and bring to a gentle boil over medium-high heat. Stir in the lemongrass, galanga or ginger, peppercorns, and half of the lime leaves or all of the lime zest; adjust the heat to maintain an active simmer.

Meanwhile, cut the butternut squash in half lengthwise. Scoop out an discard seeds, cut the squash into large chunks, and, using a paring knife, peel the chunks carefully. Cut the peeled squash into generous bite-sized pieces; you should have 3 to 4 cups. Add to the simmering soup along with the mushrooms. Increase the heat to medium-high and bring soup back to a gentle boil. Cook for 10 minutes.

Add the tofu and cook until the squash is tender but still firm and the tofu is heated through, about 5 minutes longer.

Remove the soup from the heat and use tongs to remove and discard the lemongrass, galanga or ginger, and lime leaves or lime zest. Stir in the soy sauce, salt, lime juice, cilantro, green onions, and the remaining lime leaves. Taste and add more salt, soy sauce, or lime juice if you like. Transfer to a serving bowl and serve hot.