Bún Bò Huê (Vietnamese Spicy Beef Noodle Soup)

For the broth: In a stockpot, add beef shanks, beef bones, and ham hocks, and add enough water to cover by 1 inch. Let soak at room temperature for 30 minutes to draw out any blood. Drain, rinse, then return meat and bones to the same pot. Add fresh water to cover by 1 inch, then bring to a rolling boil over high heat. Cook for 10 minutes (there should be foam and cloudy proteins that float to the top.) Drain and rinse meat and bones well, transfer to a large bowl, and set aside. Serious Eats / Vy Tran In the same large pot, heat oil and annatto seeds over medium-high heat, stirring occasionally, until oil becomes bright red, about 3 minutes. Using a slotted spoon, remove and discard seeds. Add onion, lemongrass, and chile flakes to the annatto oil and cook, stirring often until fragrant, about 30 seconds. Serious Eats / Vy Tran Add lime leaves, salt, sugar, fish sauce, MSG (if using), and pineapple (if using), along with prepared meat and bones and 5 quarts (4.7L) water. Bring to a boil, reduce heat to maintain a simmer, and cook until ham hocks are fork-tender but not falling off the bone, about 1 hour. Transfer ham hocks to a large bowl, let cool slightly, then cover and refrigerate. Serious Eats / Vy Tran Continue to cook broth until beef shank is fork-tender, 2 to 4 hours longer. Remove beef shank, transfer to cutting board, let stand until cool enough to handle, then slice beef shank 1/4 inch thick and set aside. Strain broth, discard solids, then return broth to pot. Serious Eats / Vy Tran Meanwhile, in a small pot, combine shrimp paste with 2 cups (475ml) water, and bring to a boil over high heat. Remove from heat, stir, and let sit for 30 minutes. Using a laddle or large spoon, transfer shrimp-paste liquid to the broth, being careful to leave any shrimp paste sediment behind. Season to taste with sugar and/or fish sauce. Hold broth warm over low heat until ready to serve. Serious Eats / Vy Tran For serving: Rewarm ham hocks in the broth. In each soup bowl, add 7 ounces (200g) noodles, top with 5 or 6 slices reserved beef shank, 1 ham hock, 1 slice pork blood cake, and 2 or 3 pieces steamed ham, followed by a handful each of green onions, yellow onion, and cilantro. Serious Eats / Vy Tran Return broth to a boil, then ladle enough hot broth into each bowl to cover noodles. Serious Eats / Vy Tran Serve immediately with a plate of fresh mint, banana blossom or cabbage, bean sprouts, chiles, and lime wedges alongside, as well as extra shrimp paste if desired. Serious Eats / Vy Tran