Instant mashed potato flakes are my secret ingredient for making breads fluffy. When you buy them, look for the ones that don't have any extra ingredients - no salt, spices, or preservatives. I've found several brands that are nothing but dried potatoes - that's exactly what you're looking for.
I normally use my stand mixer for kneading bread dough, but most can be kneaded by hand. In theory, you could knead this one by hand, but it's pretty stiff at the beginning which makes it harder to knead. And then, trying to add that much butter to a dough can be annoying by hand. It can be done, but it's not a whole lot of fun.
Then again, these rolls are worth it.
Parker House Rolls
Makes 12 large rolls
1 1/4 cup gently warmed* milk
2 1/4 teaspoons instant yeast
2 1/4 cups (11 1/4 ounces) bread flour
2 tablespoons sugar
1/2 cup instant mashed potato flakes
4 tablespoons unsalted butter at room temperature
1 teaspoon salt
Put the milk, yeast, bread flour, sugar, and potato flakes in the bowl of your stand mixer. Knead until the dough is smooth and elastic. The dough will be quite stiff at this point.
Add the butter and salt and continue kneading until the butter is completely incorporated. Cover the bowl with plastic wrap and set aside until the dough has doubled in size, about an hour.
Line a baking sheet with parchment paper and preheat the oven to 350 degrees. Dust your work surface with flour - you won't need much at all. Turn out the dough, pat it down to flatten it. Fold the left side towards the middle, the the top, right side, and bottom. The dough should now be somewhat square.
With a rolling pin, roll the dough to about 9 x 12 inches. Using a pizza cutter or sharp knife, cut the dough into three 12-inch strips, then cut each strip into 4 equal pieces, so you have 12 squares.
Using a chopstick, the handle of a wooden spoon, or a similar object, press a line onto each square going straight across (not diagonally) so it's not quite across the center of the square. This will help keep the dough from unfolding when it bakes. Fold the dough over at the crease, with the larger portion folded over the smaller one, like a clam with an overbite.
Arrange the folded dough on the baking sheet, leaving space between them if you don't want them to touch, or placing them nearly touching if you prefer pull-apart buns.
Cover the buns with plastic wrap and set aside until doubled in size - about 30 minutes, or half the time it took for the first rise.
When the buns have doubled in size, bake at 350 degrees until the buns are nicely browned, about 25 minutes.
Remove the buns from the pan and let them cool on a rack.
*The milk shouldn't be hot - just at that point of warm when you realize it's not chilled any more. 30 seconds or so in the microwave is just about enough. If it still seems chilly, microwave in short increments, until it feels just warm - not hot.