How to Make It
In a medium saucepan, bring the chicken stock to a simmer over moderately high heat. Reduce the heat to low and keep warm.
In a large, deep skillet, heat the olive oil. Add the onion and thyme and cook over moderate heat, stirring occasionally, until the onion is softened, about 6 minutes. Add the barley and cook, stirring, for 2 minutes. Add 1 cup of the warm stock and cook, stirring, until nearly absorbed. Continue adding the stock 1/2 cup at a time and stirring until it is nearly absorbed between additions. The risotto is done when the barley is al dente and suspended in a thick, creamy sauce, about 35 minutes. Stir in the 1/2 cup of Parmigiano-Reggiano and the butter and season with salt and pepper. Serve at once, passing more cheese at the table.