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 the wine if using and cook, stirring until absorbed, about one minute.
Add 1 cup of the warm stock and cook, stirring, until nearly absorbed.
Continue adding the stock ½ cup at a time in six additions, stirring until it is nearly absorbed between additions.
Most barley risottos are done when the barley is al dente and suspended in a thick, creamy sauce, about 35 minutes; however, I like to take this one a little 'soupier' adding another half to one cup of stock.
Stir it in until the risotto is on the loose side, then add the beans and let them cook for a minute.
Add the escarole and let it wilt and then cook for an additional minute.
Stir in the ½ cup of Parmigiano-Reggiano and the butter and season with salt and pepper.
Serve at once, passing more cheese at the table.
