Steps
- In a stand-mixer bowl, combine 1 tablespoon of instant yeast, ½ cup of granulated sugar, 1¼ cups of lukewarm water, and ¾ cup of softened unsalted butter.
- Add 2½ teaspoons of salt, 2 large eggs, 1 cup of plain mashed potatoes, and 6½ cups of all-purpose flour. Beat with the paddle on medium-high for 4-5 minutes, scraping twice, until shiny.
- Knead with the dough hook on medium for 7 minutes, scraping twice and adding a little water if dry. Round in a greased bowl, cover, and refrigerate overnight.
- Divide into two logs and place in greased 9 × 5in / 23 × 13cm loaf pans. Cover and rise for 2-4 hours, until the dough crowns 1in / 2.5cm above the rims.
- Near the end of the rise, preheat the oven to 350°F / 175°C. Bake for 25 minutes, cover with foil, and bake for 15-20 minutes, until deep golden and 190°F / 88°C inside.
- Cool in the pans for 5 minutes, then turn out onto a rack to cool completely.