To make the confit: Stem and clean the mushrooms, leaving the caps whole, except the portobellos, which can be quartered. In a colander, combine the mushrooms and sprinkle generously with kosher salt and freshly ground black pepper. Set the colander aside in a bowl, for 30 minutes to 1 hour, stirring occasionally, allowing the mushrooms to release as much liquid as possible (do not reserve the liquid). Pat the mushrooms dry with a paper towel.
Preheat oven to 225 degrees F.
In a large baking dish, combine the mushrooms with the oil, garlic, bay leaves, thyme, rosemary, and black pepper. Cover with foil, and bake for 1 1/2 hours, until the mushrooms are very tender. Transfer the mushrooms to a strainer or colander set over a medium bowl to catch the oil. Remove and discard the bay leaves, thyme, and rosemary. Reserve 1/2 cup of the oil, and save the rest of the mushroom oil for other recipes.
To make the salad: In a small bowl, combine the garlic, vinegar, mustard, salt, and season with salt and pepper, to taste. Gradually whisk in the 1/2 cup of reserved mushroom oil to make a creamy dressing.
In a medium bowl combine the mushrooms, barley, radish, carrots, green onions, and parsley; lightly toss with a little of the dressing. Season with salt and pepper, to taste.
In another medium bowl, toss the mesclun with a little of the dressing and season with salt and pepper, to taste. Reserve the remaining dressing for another use.
To serve, divide the greens among 4 plates. Top with the mushroom salad and drizzle with truffle oil. Top with the carrot curls and serve immediately.
Yield: 4 servings