Combine beef, broth, bay leaves, and lemongrass in a pot. Bring to boil, then simmer 1.5–2 hrs until tender.
Remove beef and set aside. Reduce broth to about half, (roughly 10 minutes when boiling). Discard bay leaves and lemongrass.
Heat oil in a large pan, add curry paste, and cook 3 min until fragrant.
Stir in coconut milk, cinnamon, star anise, and reserved broth. Simmer 3 min.
Add tamarind paste, fish sauce, and sugar.
Add potatoes and simmer 8 min. Return beef and cook 2–3 min until sauce thickens.
Adjust flavor if needed, thin with water, and serve over rice with peanuts, chilli, and crispy shallots.
