- In large, heavy-bottomed pot—preferably stainless steel or cast-iron—heat oil over medium-high heat.
- Season oxtail slices with salt and carefully place as many pieces as will fit in single layer in bottom of pot. Allow pieces to brown undisturbed, about 5 minutes, then carefully turn over. Sear other side an additional 5 minutes. Once evenly browned on both sides, remove meat from pot and reserve. Follow same process with remaining meat.
- Place split onions, cut side down, in bottom of same pan. Add garlic cloves and allow all to brown.
- While onion and garlic are searing, use tongs to place entire finger of ginger in center of a lit burner on high. Allow ginger to char on all sides.
- In a separate dry pan, toast toasted spices over medium heat until fragrant.
- Once onion and garlic are browned, add seared meat back to pot, along with 1½ gallons water. Slice finger of charred ginger into coins and add to pot.
- Place toasted spices with bay leaves inside cheesecloth, tie into a sachet, and place in pot. Bring entire mixture to a simmer and then reduce heat until only a few bubbles rise to top at a time. Allow pot to simmer for minimum of 3 hours, or until oxtail meat begins to pull from bone.
- Once meat is completely tender, carefully remove sachet of spices and halves of onion from pot with a skimmer. Oxtail bones may be removed or left in, depending on individual taste.
- Add fish sauce, lemongrass, and cilantro to pot. Season pho to taste with salt and sugar and reserve until ready to serve.
To Assemble and Serve
- Heat oil in sauté pan set over medium-high heat. Add peas to pan and sauté for 3 minutes, tossing gently, until peas are al dente. Add mushrooms, garlic, shallot, and ginger, then add pea tendrils and leaves. Add salt to taste and remove from heat.
- Divide softened rice noodles into 6 large bowls. Ladle as much hot pho broth as will fit into each bowl, being sure to bring plenty of oxtail with it. Evenly distribute mushroom and pea mixture among each bowl. Serve immediately.
- In center of dining table, place platter piled high with mung bean sprouts, shaved jalapeño, lime wedges, basil on the stem, and cilantro on the stem for all to season their bowls as desired. Jar of saté chili paste should be set out with small spoon so each individual can adjust the heat of pho according to personal preference.