In the northern parts of Greece, all sorts of meats, from chicken to savory meatballs to lamb and goat, are cooked in sauces based on the local, delicious, thick, strained sheep’s milk yogurt. This dish comes from the traditional cooking of the Vlachs, a once itinerant shepherd tribe, and is sometimes called vlachiko. I have modified this recipe by using boneless lamb instead of leg of lamb and replacing some of the butter with olive oil when browning the meat and vegetables.
Heat the olive oil and butter in a large, wide pan over medium-high heat and brown the lamb pieces, turning to color evenly. Add the scallions and stir until soft. Stir in the garlic and cook for a few minutes to soften. Add the rice and pour in the wine and water. As soon as the rice has absorbed most of the liquid, season the contents of the pot with salt and pepper and remove from heat.
Whisk the eggs until creamy. In a separate bowl, whisk together the yogurt and flour. Whisk the yogurt mixture into the eggs and stir in the chopped mint. Season lightly with a little salt.
Place the lamb mixture in a clay or ovenproof glass or ceramic baking dish about 3 inches/7.5 cm deep. Spread the yogurt mixture evenly over the meat. Bake uncovered for 45 minutes until the yogurt is set and lightly browned on top and then cover and cook for another 45 minutes until the lamb tender. Ten minutes before removing from oven, sprinkle, if desired, with grated kefalotyri cheese.