Place stock in a microwavable measuring cup or glass bowl. Microwave at high until hot, about 2 minutes.
Heat oil in a large Dutch oven over high. Add onion, garlic, and thyme; cook, stirring occasionally, 2 minutes. Add farro; cook, stirring occasionally, until toasted, about 4 minutes. Stir in wine. Bring to a boil; cook until nearly evaporated, about 1 minute. Add 2 1/2 cups hot stock; bring to a boil. Reduce heat to medium; simmer until farro is very tender, adding hot stock, 1 cup at a time, stirring until incorporated after each addition, about 25 minutes total. (You may have leftover stock.)
Remove from heat. Stir in grated cheese, butter, and pepper. Sprinkle with parsley and shaved cheese.