Set up: Prepare all produce and the beef as indicated in the ingredient list; rinse the rice until the water runs clear and set everything aside.
Toast the raw peanuts in a dry skillet over medium heat, stirring, until fragrant and lightly golden, 4β6 minutes; cool slightly. Blend the peanuts with 2 cups of the beef stock until very smooth, 1β2 minutes, then strain through a fine sieve; set the peanut puree aside.
Heat the vegetable oil in a medium pot to 350Β°F. Pat the potato matchsticks very dry and fry in batches until golden and crisp, 2β3 minutes per batch; drain on paper towels and keep warm. Carefully reserve 2 tbsp of the frying oil for the soup base.
Heat the reserved oil in a large heavy pot over medium-high. Season the beef chuck with half of the kosher salt and all the black pepper, add to the pot, and brown in batches until well colored, 5β7 minutes; transfer to a plate.
Reduce heat to medium, add the yellow onion, carrot, and celery, and cook, stirring, until softened, 4β6 minutes, scraping up browned bits.
Stir in the garlic, ground cumin, sweet paprika, and aji amarillo paste and cook until aromatic, 30β60 seconds.
Return the beef and any juices, pour in the remaining stock, and add the bay leaf. Bring to a boil, then reduce to a gentle simmer. Stir in the long-grain rice and cook, stirring occasionally, until the rice is just starting to soften, 10 minutes.
Add the yellow potatoes and simmer until the potatoes are tender, 10β12 minutes.
Whisk the peanut puree to loosen and stir it into the pot gradually. Simmer gently, stirring often to prevent sticking, until the soup is slightly thickened and the rice and beef are tender, 10β15 minutes. Fold in the frozen peas during the last 3β4 minutes. Remove and discard the bay leaf; taste and adjust seasoning as needed.
Ladle the sopa de mani into bowls and top generously with the crispy potato matchsticks and parsley. Serve hot.