Ingredients

Instructions

1. Prepare the butter: Remove the butter from the refrigerator, and cut it into 8 equal pieces. Set the butter aside to soften.
2. Cook the potatoes: Peel the potatoes and cut them into chunks. Place the potatoes into a small saucepot, add enough water to cover by an inch or two, and bring to a boil over medium-high heat. Once boiling, cook for about 10 minutes or until the potatoes are fully cooked and easily pierced with a knife. Drain the potatoes. Pass the cooked potatoes through a ricer or mash with a masher. Leave the potatoes to cool. Measure out the 206g (1 ½ cups) for the recipe.
3. Set up the Proofer: Set the Proofer to 78°F (25°C) and put the water tray in the middle of the warming plate. Pour ¼ cup (60 ml) of water into the tray and place the rack on top of the tray.
4. Mix the dough: To the bowl of a stand mixer, add all of the dough ingredients except for the butter. Attach the dough hook and mix on low speed for 5 to 7 minutes. Stop and scrape the bowl if necessary to fully incorporate the ingredients. On low speed, begin to add the butter one piece at a time. Wait until the butter is mostly incorporated to add the next piece. This process will take about 5 to 7 minutes. Once all of the butter is added, stop the mixer and scrape the bowl. Turn the mixer back to low speed and mix for 2 to 3 more minutes.
5. Bulk fermentation: Transfer the dough to a greased bowl and place it into the Proofer. Allow it to rise for about 1 ½ hours until doubled in size. While the dough is proofing, prepare two ¼ sheet pans (9 x 13") by lightly greasing or lining them with parchment paper.
6. Divide and shape the buns: Turn the dough onto a lightly floured surface. Gently press down on the dough to deflate it, and then divide it into 12 equal pieces (120g each). Roll each piece into a ball. Once all the pieces are rolled, press down on the top of each round to flatten into a disc measuring about 3.5” (9cm) in diameter. Place 6 rolls per pan (in two rows of three).
7. Final proof: Check that the Proofer is still set to 78°F (25°C) and there is still water in the water tray. Place one pan of buns on the bottom rack of the Proofer. Place the accessory rack inside of the Proofer and place the second tray on top of the accessory rack. Leave the buns in the Proofer to rise for 60 to 75 minutes. Toward the end of the proofing time, preheat the oven to 350°F (177°C).
8. Bake: In a small bowl, use a whisk or fork to combine the reserved egg white with the milk. Remove the buns from the Proofer. Using a pastry brush, apply the egg wash to the buns. Sprinkle with sesame and salt. Place the pans in the oven and bake for 18 to 20 minutes until golden brown. Transfer the buns to a rack to cool.