In a saucepan, bring the broth to a boil. Cover and turn off the heat.
Heat 1 tablespoon of olive oil in a deep skillet over medium heat. Add onion and saute until soft. Reduce heat to low.
Add barley and stir to coat with oil. Add wine and cook, stirring, until wine is absorbed.
Add hot broth, 1/2 cup at a time, stirring frequently and adding more as broth absorbs. (This should take about 30 minutes. You may have broth left over, or you may need to add more to get barley to desired consistency.)
Put remaining olive oil in a skillet over medium heat. Add mushrooms and shallots and saute until mushrooms are golden and shallots are soft.
Stir mushroom mixture and basil into barley, season with salt and pepper, and sprinkle with Parmesan cheese.