This recipe is my own creation, but I found it tasty!
2 lamb hearts (about two pounds), cubed 1 lb chicken hearts, halved 2 pork hearts (about one pound), cubed kosher salt 3 T butter 1 T olive oil red wine 2 md red onions, cut into 1/2" wedges 1/2 c steel-cut oats 1/2 c barley grits (see note) 1/2 c rye grits (see note) 1 qt beef stock 1 c water 1 oz dried porcini mushrooms dried herbs and spices: bay leaf, juniper berries, rosemary, sage, thyme, etc 1 c huckleberries (or other small, round, berries, e.g. lingonberries), fresh or frozen
Meat Note: The lamb and pork hearts should be cubed to roughly the size of half a chicken heart.
Barley and Rye Note: I happened to have steel cut oats, rye berries, and hulled (not pearl) barley to hand. I ran the rye and barley through a coffee grinder, in pulses, until they looked like the steel-cut oats.
Preheat oven to 325°
Place the cut-up hearts in a bowl and sprinkle liberally with kosher salt. Let them rest this way for twenty minutes while you prepare the other ingredients. Melt the butter in a four-quart or larger oven-safe Dutch oven with lid over medium-high heat and add the olive oil. When the oil is hot, add half the hearts and brown on all sides, stirring occasionally. When hearts are browned on all sides, remove to a clean bowl and repeat with the second half of the hearts. Remove these to the same bowl and reserve, being careful to leave as much oil in the Dutch oven as possible.
Once all hearts are browned, add onions and cook, stirring frequently, until starting to become translucent, 3-5 minutes. Remove these to the same bowl as the hearts.
Pour about 1/2 c red wine into the cooking vessel and scrape browned bits from bottom of pan. Once the wine has reduced slightly, add barley, oats, and rye, stirring continuously. Once grains have soaked up the liquid, add stock and return hearts and onions to pan. Increase heat to high, bring to a boil, then reduce to a low simmer. Add berries, herbs, and spices and stir to combine.
For extra evaporation protection, cover the top of the Dutch oven with aluminum foil before putting on the lid, then put the stew in the oven. Bake without stirring until grains are done and hearts are tender, 2-3 hours, stirring and checking occasionally after the first hour.