Boil potato until tender. Drain cooking water, reserving ¼ cup for use in the rolls. Finely mash the potato and measure out ½ cup. Let cool to room temperature.
In the bowl of a stand mixer, mix together mashed potato, butter, sugar, honey salt and egg with paddle attachment. Mix together on medium speed for about 2 minutes.
Combine yeast, warm milk and potato water and pour into mixer bowl. Mix on low speed until incorporated.
Gradually add flours, about a ½ cup at a time, until a soft dough forms. Switch to the dough hook attachment and knead on low speed for 5 minutes, adding more flour if necessary to achieve a soft dough that is slightly tacky but not sticky.
Transfer the dough to a lightly oiled bowl, turning once to coat. Cover with plastic wrap and let rise in a warm place until doubled in bulk, about 60-90 minutes.
Line a baking sheet with parchment paper. Turn the dough out onto a lightly floured surface and punch it down. Separate into 16 equal pieces and shape into rolls.
Place rolls on prepared baking sheet, about 1 ½ inches apart. Sprinkle the rolls with a dusting of flour. Cover with a clean kitchen towel and let the dough rise again until the rolls have grown into each other, about 30-45 minutes.
Preheat oven to 400℉.
Bake rolls for 12 minutes, or until golden brown. Serve warm.
Notes
When making this recipe you will use boiled russet potatoes to give the best flavor and moisture to this dinner roll recipe.