Ingredients

  • 2 medium onions, peeled and quartered
  • 1 head garlic, split horizontally
  • one 4-inch piece ginger, split in half horizontally
  • 2 serrano chilies, split in half horizontally, plus 2-3 additional, thinly sliced, for serving
  • 2 cinnamon sticks
  • 4 star anise
  • 2 1/2 teaspoons coriander seeds
  • 7 cloves
  • 1 tablespoon black peppercorns
  • 2 teaspoons fennel seeds
  • 5 cardamom pods
  • three pieces bone-in beef shank, cut into 2-inch rounds, about 5-6 pounds total
  • 8 cups low sodium chicken broth
  • 2 teaspoons salt or 2 teaspoons fish sauce, plus additional for serving
  • 1 lb thin rice noodles, soaked in hot water until tender for 30 minutes
  • 1 cup bean sprouts, for serving
  • lime wedge, for serving
  • mixed herbs, such as cilantro, Thai or italian basil, and mint, for serving
  • thinly sliced scallion, for serving

Method

  • Preheat broiler.
  • Place onion, garlic, ginger, and serrano chiles on a small baking sheet and broil, rotating until charred, about 8 minutes. Remove from broiler and add cinnamon, star anise, coriander, cloves, peppercorns, fennel, and cardamom. Return to broiler until spices are toasted and aromatic, about 30 seconds to a minute more. Transfer to crock pot, along with beef shanks and chicken stock. Add salt or fish sauce, and enough water to cover shanks by 1/2-inch, about 8 cups.
  • Place lid on crock pot and let cook, at least 8 hours and up to 12 for an even fuller flavor, until meat is falling off the bone.
  • Remove beef from crockpot. With a spider or mesh strainer, remove all aromatics from the pot. With a large spoon, skim fat. When beef is cool enough to handle, shred into bite-sized pieces and return to broth. For best results, chill broth and skim fat; reheat before serving. Alternatively, skim fat while soup is warm with a large spoon. Season to taste with salt or fish sauce.
  • Divide broth and meat among serving bowls and top with noodles, bean sprouts, lime wedges, herbs, scallions, and chiles. Serve.