Place ginger, chillies, lemon grass, brown sugar and galangal in an electric grinder. Pulsate for a few seconds till the mixture form a paste. Place beef cubes in a heavy-based pan. Add in the chilli paste. Cook over low heat until the beef change colour. Stir in the vegetable stock, turmeric and soy sauce. Cover and simmer very gently for 2 hours till the beef is tender. Season to taste. Add in chopped shallots, garlic, tamarind juice and fish sauce. Serve with freshly cook green beans and garnish with sliced red chilli.