Boil the potatoes until tender, drain, peel and mash while slightly warm.
Combine flour, yeast, warm water, salt and optional olive oil. Knead for 8 to 10 minutes until soft and smooth.
Cover the dough and rest for 35 to 45 minutes.
Heat olive oil in a skillet. Sauté the onion until soft, then stir in tomato paste for 1 minute.
Add mashed potato, pul biber, black pepper, salt and optional parsley. Mix thoroughly and leave to cool.
Divide the dough into 8 equal balls. Cover and rest for 10 minutes.
Roll each dough ball into a thin round or oval approximately 25 to 28 cm wide.
Spread potato filling over one half, leaving a border around the edge.
Fold the dough into a half-moon and press the edges firmly to seal.
Cook in a dry pan over medium heat for 2 to 3 minutes per side until golden with toasted spots.
Brush with melted butter or olive oil while hot and serve warm.