Bring stock and farro to a boil in a large saucepan; cover, reduce heat, and simmer 25 minutes or until farro is al dente. Drain in a colander over a bowl, reserving cooking liquid.
Heat a large nonstick skillet over medium heat. Add oil; swirl to coat. Add squash, onion, carrot, and celery; sauté 5 minutes. Stir in 1/4 cup reserved cooking liquid. Reduce heat to low; cover and cook 7 minutes or until vegetables are tender. Stir squash mixture into farro mixture. Stir in almonds, parsley, thyme, sage, salt, and pepper. Spoon into an 11 x 7-inch glass or ceramic baking dish. Cover and keep warm until ready to serve. Stir in additional reserved cooking liquid as needed just before serving.