Peel the peppers and dry them gently. Beat the egg with the mashed potatoes, grated parmesan cheese, a little salt and garlic powder and add just enough yogurt, to produce a thick paste, in which you can soak the peppers.
Optionally, you can add other spices to taste. Lay out baking paper into a tray, and gently grease it. Soak the peppers in the crumbing and arrange them in the tray. Pour in a trickle of olive oil or oil over them.
Put the peppers to bake in a moderately hot oven until they get a delicious tan.