Put the stock, water, farro, and salt in to a 2 - 3 quart sauce pan. Cover and bring the liquid to a boil then reduce the heat to medium low and simmer for 20 minutes. When the farro is plump and easy to chew. Drain any excess liquid from the pan and place the cooked farro into a large bowl.

While the farro simmers: Brown the sausage, remove casings if using link sausage. Cook in a skillet over medium high heat and break the sausage into small crumbles while it cooks, about 8 minutes. Transfer the cooked sausage crumbles to a paper towel lined plate. Drain any liquid fat from the pan but do not wipe clean.

Replace the skillet on the heat and add the onion and mushrooms. Stir frequently until the onion has softened and the mushrooms have browned, about 5 minutes. Add the sausage, onion, and mushrooms to the large bowl with the farro and stir to combine.

Preheat the oven to 350 degrees. Place a large pot of water on the stove, cover, and bring to a boil.

Prepare the bell peppers: Slice across the very top of each pepper to remove the stem area. Use a small knife to trim away the core, seeds, and white ribs. Cook the cleaned peppers in the boiling water for two minutes then remove, drain, and let dry.

Return to the stuffing mixture and stir in the salt, pepper, and 1 cup of cheese. Fold in the tomatoes. Taste the stuffing and add a few more pinches of salt if it needs a bit more pep.

Arrange the softened peppers, cut end up, in a large baking dish. Fill each pepper with 1 cup of stuffing. Sprinkle the remaining grated cheese over the stuffed peppers.

Cover the dish with foil and bake in the hot oven for 15 minutes then remove the foil and continue baking for an additional 10 minutes. Serve hot.