1–In a medium pot, heat the oil over medium heat. Add the onion and cook until it starts turning golden, about 3 minutes. Add the celery, carrot, garlic, thyme, and oregano and cook for another 2 minutes. Throw in the barley, tomato, and vinegar and stir. Add the broth, salt, and pepper and let it come to a low simmer. Cook, uncovered, until all the broth is absorbed and the barley is tender, about 15 minutes.
2–While the barley is simmering, heat your oven to 375° F. Cut the tops off the bell peppers and scrape out the seeds. Place them in an oiled pie place or loaf pan, something where their asses won’t be sliding around once they’re stuffed.
3–When the barley is done, fold in the beans and turn off the heat. (This filling can even be made a day or two ahead of time, no fucking problem.) Fill the bell peppers up to the top with the filling, cover them tightly with foil, and bake until the peppers are tender, 45 minutes to 1 hour. Let them rest for 5 minutes after coming out of the oven, ’cause those fuckers are hot. Top with the parsley and serve.