Wash potatoes thoroughly and cook in boiling salted water for about 20 minutes. In the meantime, clean and wash the beans and cook in boiling salted water for 12-15 minutes. Wash parsley, dab dry and chop finely. Cut butter into cubes. Heat 1/8 litre water, stir in sauce powder with a whisk, bring to the boil and gradually add butter over a low heat.
Drain potatoes, rinse with cold water, peel and sprinkle with parsley. Drain the beans and arrange on a plate with potatoes, ham and some sauce. Serve garnished with parsley. Add remaining sauce extra