Preheat oven to 400° Line a rimmed baking sheet with aluminum foil; spray with non-stick spray.

Combine the farro, stock, and 2 teaspoons salt in a large, heavy saucepan; bring to a boil over high heat. Cover and simmer, stirring occasionally, following package instructions until the farro is just tender. Note: toward the end of the cooking time, be sure to check it often as you want it to retain just a bit of its structure and remain “toothsome.” Remove from heat, drain any excess water and set aside.

Meanwhile, combine the sweet potatoes, onion and thyme in a medium bowl. Whisk together the olive oil, balsamic vinegar and 1/2 teaspoon salt in a cup for dressing. Add 2 tablespoons of the dressing to the sweetpotato mixture; toss to combine. Arrange in a single layer on the prepared pan; roast in the oven for about 20 minutes, tossing vegetables after 7 and 15 minutes to achieve even browning.

Remove from the oven and toss with cooked farro, 1/2 cup goat cheese, the walnuts and remaining dressing. Transfer to a serving bowl and scatter remaining goat cheese over the top. Serve.