Cut the Beef Chuck into 1–1½ inch cubes and pat dry; season lightly with salt and pepper.
Heat a large, heavy-bottomed pot over medium-high heat and add a splash of Neutral Oil. Brown the beef in batches until well-seared on all sides, removing each batch to a plate—you want good color but not fully cooked.
Lower the heat to medium and add another small drizzle of oil if needed. Add the sliced Onions and whole spices: a Cinnamon Stick, a few Green Cardamom Pods (lightly crushed), a Bay Leaf, and a Star Anise. Sauté until the onions are soft and the spices are fragrant, about 4–5 minutes.
Stir in the Massaman Curry Paste and cook for 1–2 minutes to bloom the flavors, scraping any browned bits from the bottom of the pot.
Pour in about one can of Full-Fat Coconut Milk and a cup of Water, stirring to combine. Return the seared beef to the pot and bring to a gentle simmer.
Add the peeled and chunked Potatoes and a couple of tablespoons of Tamarind Paste, then season with Fish Sauce and a palm-sized amount of Palm Sugar to taste. Stir well.
Reduce the heat to low, cover partially, and simmer gently until the beef and potatoes are tender, about 1–1½ hours depending on the cut—check occasionally and add a splash of water if the curry reduces too much.
About 10 minutes before the curry is done, stir in roughly chopped Roasted Unsalted Peanuts (reserve a few for garnish) and adjust seasoning—more fish sauce for saltiness, tamarind for brightness, or palm sugar for sweetness.
While the curry finishes, rinse the Jasmine Rice under cold water until the water runs clear, then cook according to package instructions (typically 1 part rice to 1¼–1½ parts water, bring to a boil then simmer covered 12–15 minutes).
Remove and discard the whole spices set aside (cinnamon stick, bay leaf, star anise), taste once more, and serve the curry hot over jasmine rice, sprinkled with the reserved peanuts.
