Place the diced potatoes in a saucepan and cover with cool water. Bring to a gentle boil and cook until the potatoes are fork-tender. Drain the potatoes, mash them until smooth, and let it cool to room temperature.
In a small bowl, combine warm water and sugar. Sprinkle the yeast over the mixture and let it sit for about 5 minutes, or until foamy.
In a large mixing bowl, combine the cooled mashed potatoes, yeast mixture, vegetable oil, salt, and 2 cups of bread flour. Stir well to combine.
Gradually add the remaining flour, 1/2 cup at a time, until a soft dough forms. You may need slightly more or less flour, depending on the moisture content of the potatoes.
Transfer the dough to a lightly floured surface and knead for about 5 to 7 minutes, or until the dough becomes smooth and elastic.
Shape the dough into a ball and place it in a greased bowl. Cover with a clean kitchen towel and let it rise in a warm place for about 1 hour, or until doubled in size.
Gently punch down to deflate the risen dough to release any air bubbles. Transfer it to a lightly floured surface and knead gently to remove any excess air.
Shape the dough into a loaf and place it in a greased 9×5-inch bread pan. Cover with the kitchen towel and let it rise for another 30 to 45 minutes, or until it reaches just above the rim of the pan.
While the dough is in its second rise, preheat the oven to 375°F (190°C).
Bake the potato bread in the preheated oven for 30 to 35 minutes, or until the top is golden brown and the loaf sounds hollow when tapped, or internal temperature reaches 190°F.
Remove the bread from the oven and let the loaf cool in the pan for a few minutes, then transfer to a wire rack to cool completely before slicing.
Finally, once cool, slice and serve!