Heat butter in a pan over medium heat. Add the thinly sliced potatoes, season with salt, and cook until golden and tender.
Push the potatoes to the side of the pan and crack the eggs in. Scramble them lightly or cook them to your preference.
Place the tortilla or flatbread in the pan and spread the potatoes and eggs evenly over one half.
Sprinkle cheese and any optional seasonings over the top.
Fold the tortilla in half over the filling and press gently. Cook for 1-2 minutes per side until golden brown and crispy.
Slice and serve warm with your favorite dipping sauce or fresh herbs.