Blueberry brunch challah, with variations

1 bag Trader Joe's dried blueberries (alternate filling: chopped walnuts)
1 stick butter
1/2 cup or more honey or brown sugar (preferably honey, but brown sugar works too)
2 eggs
1 cup milk and/or water (this may be an underestimate)
2 packets yeast
2 cups whole wheat flour and/or 1 cup oats
4-8 cups white bread flour
some cardamom or other spices of choice
2 tsp salt
a bit more brown sugar and butter
2 pie pans

Put butter in a microwavable bowl. If using honey, put it in too. If
using oats, put them in too along with some extra liquid. If both
loaves will be blueberry, put the blueberries in too. Microwave until
butter is melted and/or oats are at least partly cooked. Add eggs,
milk/water, and brown sugar (if you didn't use honey), mix well, and
cool to a nice lukewarm temperature that will make the yeast happy.
Look at the bowl you're using and decide if it's big enough to hold
the flour too; transfer the goop to a larger bowl if not.

Sprinkle on yeast and wait a few minutes for it to proof. Add the
flour(s), spices if you want, and salt. (You don't want a stiff dough,
so don't add too much flour to start out with.) Mix to form a soft but
not sticky dough and knead for several minutes until the dough is
pliable. If you want to make one loaf blueberry and one loaf something
else (eg walnut), cut the dough in half and knead
a couple handfuls of blueberries into one half and a couple handfuls
of whatever else into the other half. Lightly oil one (or two)
bowl(s), form dough into ball(s), put the ball(s) into the bowl(s),
and turn the ball(s) over to coat with oil on all sides. Cover and let
rise in a warm place until doubled, 1-2 hr.

Prepare the pans by buttering and sprinkling with brown sugar, as for
cinnamon rolls.

Turn dough out onto a lightly floured surface. If the dough isn't
already divided in half, cut it in half. Slap each half on the surface
a couple times to deflate. For each half: cut into three equal-sized
pieces. Elongate each piece into a 1.5-2 foot long, ~1 inch diameter
rope. Some blueberries will be falling out; this is fine. Lay the
three strands side by side and braid, starting in the middle and
working toward each end (this makes for a more symmetrical braid).
Gather up any blueberries that have fallen out and sprinkle them in
the prepared pan. Loosely coil the braid around itself to form a
circle almost as big as the pan, and place it in the prepared pan.
Cover and let rise in a warm place.

Preheat the oven to 400 F (hotter or cooler ok). Bake 25-45 minutes
until nicely browned and otherwise done. If they brown too fast, cover
with foil while they finish baking. Brush the tops with butter if you
want, and cool in the pan. Tear off chunks and eat them!