In a large bowl, mix together the mashed potatoes, beaten eggs, and softened butter.
Stir in the sugar, salt, yeast, and warm filtered or bottled water.
Mix in the flour 1 cup at a time, sifting before each addition, until the dough can be easily kneaded by hand.
Turn the dough out onto a floured board or surface and knead it until it is smooth and elastic. ( Kneading helps develop the gluten and create long strands, which make the end product more springy.)
Grease a bowl with olive oil. Add the dough and flip it over inside the bowl so all sides are lightly greased. Cover the bowl and let the dough rise for 1 to 2 hours, until doubled in bulk. (Putting it in the warmest place in your kitchen helps it to rise.)
Punch down the dough by making a fist and pressing firmly in the center of the dough.
Fold the edges of the dough into the center of the bowl to form a ball. Turn it out onto a lightly floured board and briefly knead out the bubbles.
Divide the dough in half and make 2 loaves.
Place each loaf in a greased 8 x 4 x 2-inch bread pan. Cover and let the dough rise a second time for 40 minutes or until doubled.
Bake at 375 F for 40 minutes or until the bread sounds hollow when the top is tapped.
Remove the loaves from the pans and let them cool on a rack. Enjoy toasted, as a sandwich, alongside a meal, or simply as is.