While the farro is simmering, add the olive oil to a large, deep skillet over medium heat. Add the shallots. Cook for 2 minutes, stirring constantly, or until the shallots are soft. Add the garlic and cook for another 2 minutes, stirring constantly. Add the mushrooms to the pan and give them a pinch of salt. Cook, stirring frequently, for 5-8 minutes, or until the mushrooms have released their juices and are soft, tender, and reduced in size. Add the white wine to the skillet, if using, and continue cooking until the wine has almost completely cooked down (a couple minutes). Stir in the thyme.
When the farro is ready, add it to the skillet and stir everything well to combine. Add vinegar and additional salt and pepper to taste. Heat through, folding in a protein of choice, if desired. Serve.
Leftover farro will keep in an airtight container in the fridge for up to 4 days.