Mash the potatoes with a fork and add to a stand mixer bowl with all the other ingredients minus the butter. Fit the mixer with a dough hook and knead for 10 minutes, then add the butter and knead for another 10 minutes until you have a smooth, shiny dough. Cover the bowl and let rise in a draft-free environment until double in size, about 1-1 ½ hours.

Line a baking sheet with parchment paper or silpat covers.

Tilt the dough out onto a lightly floured surface, and dive the dough into 24 pieces, about 1 ½ oz each (45 grams), and place the buns close to each other to the prepared baking sheet. The idea is for them to rise and touch each other so they are almost like pull-apart buns when they come out of the oven. Cover and let rise for another 45 minutes.

While the rolls are rising, preheat the oven to 550°F (275°C). Once ready to bake the rolls, brush them with water and sprinkle with poppy seeds.

Place the sheet tray with the buns on the middle rack of the oven, reduce the temperature to 480°F (240°C) and bake for about 10-12 minutes or until nice and golden up top.

Remove from the oven, slide the buns off the sheet tray by carefully dragging the parchment paper, and let them cool on a rack before digging in!