Set a large, heavy-bottomed, oven-safe skillet or Dutch oven over medium heat & add the olive oil. Add the shallots, fresh mushrooms, barley, salt, & pepper. Sauté until the vegetables have softened slightly & the barley begins to give off a nutty, toasted fragrance, 5–7 minutes. Bring the heat to high while stirring & add the wine. Continue stirring until about half of the wine has been absorbed/reduced. Stir in the vegetable broth & rehydrated mushrooms. Remove from the heat.