Yellow curry with beef (gang garrieh nua)

500 g (1 lb) roast beef
400 ml (13 1/2 fl oz) coconut milk
1 tb yellow curry paste
2 tb brown sugar
3 tb fish sauce
5 tomatoes
2 tb unsalted peanuts

1. Slice beef into 1-2 cm thick slices.
2. Heat coconut milk and curry paste in a pot. Add beef and let simmer for one hour.
3. Add tomatoes and let simmer for three minutes. Season with fish sauce and sugar.
4. Sprinkle with peanuts before serving.