Add 1/2 cup flour, yeast, sugar and salt to stand mixer bowl; stir to combine. In a saucepan or microwave-safe dish, warm milk and oil to 120-130°F.
Add warm milk mixture to flour mixture. Using a paddle attachment, beat for 4 minutes on medium speed. Add egg, potato, and onion; beat 2 to 3 minutes. Switch to dough hook attachment. Gradually add enough remaining flour to make a firm dough. Knead 5 to 7 minutes until smooth and elastic. Use additional flour if necessary. (NOTE: For hand mixing: following above steps, mix ingredients in large mixing bowl using a wooden spoon or dough whisk. Knead on floured surface until smooth and elastic.)
Place dough in lightly oiled bowl and turn to grease top. Cover; let rise until indentation remains after poking dough with finger down to second knuckle.
Turn dough onto lightly floured surface; punch down to remove air bubbles. Roll or pat into a 14x7-inch rectangle. Starting with shorter side, roll up tightly, pressing dough into roll. Pinch edges and ends to seal. Place in greased 9x5-inch loaf pan. Cover; let rise until indentation remains after touching.
Preheat oven to 375°F.
Bake in preheated 375°F oven 30 to 40 minutes. Remove from pan; cool on wire rack.
Notes
Get Bread Machine Method here.Note: Bake potato in microwave 4 to 5 minutes on “HIGH.” Split open and allow to cool 15 minutes. Mash with fork and measure.Photo by Stephie Cooks.