There is nothing like a sweet potato roll with a smear of horseradish mustard, some collard greens cooked for hours, and thin slices of real Virginia country ham. I had that exact canape at a wedding in Virginia sometime in the last 30 years. I came home straight away and attempted to figure out the recipe. I've been serving them for years at luncheons, brunch and Thanksgiving leftover day. (PS I've been thinking about a bread pudding made with leftover rolls, adding the horseradish, mustard, greens and ham right into the baking dish... ) —MrsWheelbarrow
Heat the yogurt, sugar, butter & salt just until the butter is beginning to melt. Remove from the heat. Stir to melt the butter completely. Let cool slightly (it should not be more than 100°)
In a large bowl, combine the milk mixture, the potato, the ginger and the yeast. Stir well to completely incorporate. Add the egg, and stir well again. Congratulations, you have now made a sponge.
Add 1 cup oat flour and 1 cup all purpose flour to the sponge and stir well. Allow the mix to stand until it bubbles - about 15-20 minutes.
Add another cup of all purpose flour and mix with a wooden spoon or use the dough hook on your mixer. Continue to mix/knead in the mixer until it's very moist and elastic.
Turn this mass out onto a well floured board (I put about 1/2 cup of flour on the counter before turning out the dough.) Lift the dough with a bench scraper and fold the dough in half, press out with the heel of your (well floured) hand, turn the dough, lift again, fold again, press again, and so on until it comes together.
Allow the dough to rest for 10 minutes. This will help the flour absorb the moisture and will keep you from adding more flour than necessary. The less flour added at this point, the lighter your roll.
Knead the dough gently, just lifting, folding, pressing, turning, lifting, folding , pressing and turning until it is a smooth, elastic ball.
Place the dough in a lightly oiled bowl and allow it to rise at room temperature for about an hour, until doubled in size.
FORM THE ROLLS: Segment dough into 12 or 24 pieces. (I weigh the dough, then measure out each roll for consistency.) Form round balls, rotating and tucking the dough into the bottom of the ball to make a smooth, elastic top. Place the rolls about 2" apart on a parchment lined sheet and allow them to rise for another hour, until doubled again.
Preheat the oven to 350. Brush the top of the rolls with melted butter, then lightly sprinkle with salt & sugar.
Bake rolls for about 17-20 minutes, to an internal temperature of 200°. They should feel very light and be slightly browned on the bottom. Cool on racks.
You can freeze these rolls and then reheat in a 350 oven for 5-8 minutes.