Heat the vegetable oil in a large heavy-bottomed pot or Dutch oven over medium-high heat. Add half the coconut milk and cook until the oil starts to separate from the milk, about 3-5 minutes.

Stir in the Massaman curry paste and fry for 2-3 minutes until it becomes very fragrant and darkens slightly.

Add the beef cubes to the pot, tossing them in the curry mixture to coat thoroughly, then pour in the remaining coconut milk and the beef broth.

Add the cinnamon stick, star anise, and cardamom pods, then reduce the heat to low, cover, and simmer gently for 90 minutes until the beef is becoming tender.

Stir in the potatoes, onion wedges, roasted peanuts, fish sauce, tamarind paste, and sugar.

Continue to simmer uncovered for another 30 minutes, or until the potatoes are tender and the sauce has thickened to a rich consistency.

Taste the curry and adjust seasoning if needed, adding more sugar for sweetness or fish sauce for saltiness.

Remove the whole spices (cinnamon, star anise, cardamom) before serving hot with steamed jasmine rice.