Cheesy Mashed Potatoes with Greek yogurt might just be the ultimate Mediterranean diet comfort food! Serve this with a great roasted chicken, such as my recipe for Roasted Chicken Stuffed with Figs and Olives. This Greek recipe for mashed potatoes calls for three Greek cheeses AND Greek yogurt. The cheeses, Greek feta, graviera and kefalotyri, add tang and that gooey deliciousness that melted cheese gives us, while the yogurt adds a creaminess and underlying tang that will surprise you.