Heat olive oil in a small sauté pan over medium. Add shallots and sauté until they begin to become fragrant. Add prosciutto. Stir over medium heat until prosciutto begins to crisp. Remove shallots and prosciutto to a small plate covered with a paper towel to drain and cool.

In a medium bowl, combine prosciutto and shallots, peas, water chestnuts, yogurt, mayonnaise, garlic powder and salt. Stir to combine. For best results, let sit in refrigerator for an hour or so to give all of the flavors a chance to meld.