Add salt, unsalted butter, flour and milk into a large bowl. Stir to mix
Use your hand to knead the dough till it become smooth and turns into elastic ball. Keep in the refrigerator and set aside.
Making the Potato Filling
Place the potato and pour water into the cooking pot.
Once the potato is boiling, lower to heat and let it simmer for 10 to 15 minutes or until it becomes soft.
Drain water from the potato and wait for 5 minutes to let it cool down.
Transfer the potatoes into the plate bowl and mash it till it's soft
Add salt and mayonnaise in the bowl. Mix to combine till smooth. Set aside.
Assembling and Cooking the Bread
Remove the dough from the refrigerator and transfer into the clean table.
Use the rolling pin to roll into 8-10 inches circle. It doesn't have to be the exact measurement.
Sprinkle the shredded mozzarella cheese into the center followed by spreading the potato filling above the cheese, and then sprinkle the shredded cheese again on top of it.
Fold the edges and then bring it toward the center to close the dough. Pinch the dough to completely cover the filling
Flip the dough bread, and gently roll it to create a smooth circular shape.
Brush the pan with vegetable oil and then place the bread on the pan in low heat.
Let it cook for 3 minutes or until it turns into golden brown. Flip to the opposite side and repeat the process.
Transfer into the wood serving board and let it cool down before cutting into 8 pieces.
Notes
To know the step-by-step instruction properly, look at the picture on the post
You can add garlic paste or powder if you want to add a garlicky flavor to the bread.