Stir the yeast and 1 tablespoon of the brown sugar into the warm water and let it stand 7 to 10 minutes, until foamy and domed.

Whisk the bread flour, remaining 2 tablespoons brown sugar, cinnamon, ginger and salt in a large bowl. Add the yeast mixture and the cooled sweet potato mash and stir to a shaggy dough.

Knead 10 to 12 minutes by hand or 8 minutes on medium low with a dough hook, until a stretched piece is thin enough to see light through. The dough should stay stiff and slightly dry. Do not add water.

Cover and let rise in a warm spot 60 to 75 minutes, until roughly doubled.

Punch the dough down and divide it into 8 equal pieces, about 115 grams each. Roll each into a tight ball, push your thumb through the center and spin the ring on two fingers until the hole is about 1 ½ inches wide.

Set the rings on a floured tray and rest 20 minutes. Heat the oven to 425 degrees F.

Bring a wide pot of water to a rolling boil and stir in the baking soda. Boil 2 or 3 bagels at a time for 60 seconds, flip with a slotted spoon and boil 60 seconds more, keeping the water at a full boil.

Drain the bagels briefly and set them on a parchment lined sheet pan. Sprinkle with sesame seeds or everything seasoning while the surface is still wet.

Bake 22 to 25 minutes, until deep golden brown and firm to the touch.

Cool on a rack at least 20 minutes before slicing, or the crumb will compress under the knife.