Savory sweet potato dinner rolls

Peel the sweet potato and cut it into uniform one inch pieces.

Put the pieces in a small saucepan, barely cover with water - even a quarter inch is enough - bring to a boil and simmer vigorously until very tender to a fork, about 15 or 20 minutes.

Chop two tablespoons of rosemary.

Put half a cup of the total three and a half cups of all purpose flour into the mixing bowl.

Lift the cooked sweet potato out with a slotted spoon, leaving the water boiling, and set it aside.

Measure half a cup of the boiling sweet potato water and pour it over the flour, working it together with a spatula into a stiff paste; this is the tangzhong.

In the same saucepan over medium to medium high heat, fry two tablespoons of the butter with the rosemary about two minutes, until fragrant and the bubbling subsides and the butter turns golden brown, then take it off the heat.

Add the cooled sweet potato and the rosemary butter to the cooled flour paste in the mixer bowl.

Add half a cup of room temperature sour cream, two room temperature large eggs and two tablespoons of sugar.

Add the remaining three cups of all purpose flour, one and a half teaspoons of instant yeast and the kosher salt.

Mix on the lowest setting, then raise one notch, adding a tablespoon of flour at a time - nearly four tablespoons in all - until the dough pulls away from the sides of the bowl.

After about 10 minutes of low and slow mixing, add six tablespoons of room temperature butter in tablespoon-size pieces, one at a time, scraping down before the last piece.

Continue mixing a few more minutes until the dough is smooth, supple and non-sticky, then form it into a tight round.

Cover and rise at room temperature until about 50% expanded, about an hour depending on the kitchen.

Chill in the fridge anywhere between eight and 18 hours.

Smear one of the remaining tablespoons of butter into the bottom and sides of the pan.

Punch the cold dough down, work it into a square and divide it with a bowl scraper into a four by four grid of 16 pieces.

Pinch the four edges of each piece together, set it seam side down and work it in rapid little circles under a cupped hand into a smooth dome, then place it in the skillet evenly spaced.

Cover with a kitchen towel and rise at room temperature until nearly doubled, a little over an hour; an oiled finger poked in should spring back leaving a slight indentation.

Beat the remaining egg and brush a thin even layer of egg wash over the risen rolls.

Bake at 350 until dark golden brown all over and shiny, between 20 and 25 minutes.

Glaze with the remaining two tablespoons of butter straight out of the oven and let them cool a little before pulling apart.