Slice beef into small cubes. Rub meat ginger and pepper. Leave for about 30 minutes.
Heat oil then saute meat with onions, garlic and tomato paste. Mix in coconut milk. Mix in curry powder slowly. Add more if needed.
Gather the lemongrass leaves to make a small bow and tie a knot to hold these in place next its bulb. Drop into the mixture then star anise. Let the mixture boil then let simmer until meat is tender and sauce thickens.
Stirring occasionally, add peanut butter and potatoes. Continue cooking until potatoes are tender. Remove tanglad. Transfer mixture to serving plate and serve.