Peel the potatoes and cut them into circles. Arrange them in a baking dish and pour the melted butter. Preheat oven to 200 ° C and is ready put the mashed potatoes soften remove the pan and sprinkle with grated feta cheese, then again put in the oven for about 2-3 minutes and remove. Once you have gone cold water them with the following sauce: Mix the yogurt, mayonnaise, salt, garlic (it is better to be crushed) and parsley (chopped), mix until a homogeneous mixture. Allow the dish to cool and serve. In the dish can add skinless sausages, sliced ​​on the potatoes before they sprinkle with the feta cheese.