1Heat Potatoes, Sauce Mix and water to boiling in 4-quart Dutch oven over high heat, stirring occasionally.
2Reduce heat; simmer uncovered about 25 minutes, stirring occasionally, until potatoes are tender.
3Remove from heat; stir in mayonnaise and mustard. Stir in ham and peas. Spoon into serving bowl; cover and refrigerate 3 to 4 hours or until chilled. Stir before serving.