Melt butter in a large skillet; add veal, and cook until browned. Add onion; sauté until tender.
Add curry powder and half-and- half; stir well. Cover and simmer 15 minutes.
Combine water, flour, and vinegar; stir until smooth. Add flour mixture to curry mixture; cook, stirring constantly, until mixture is thickened and bubbly. Stir in salt, mustard, and garlic powder.
Serve veal mixture over hot cooked rice with several of the following condiments: (about 3/4 cup each) chutney, flaked coconut, chopped hard-cooked egg, crumbled cooked bacon, salted peanuts, and sautéed onion.