Mixed Mushroom Bruschetta with Truffle Vinaigrette

Ingredients

• Black Truffle Vinaigrette
• 2 tablespoons extra-virgin olive oil
• 2 tablespoons Champagne vinegar
• 1 tablespoon black truffle oil
• ½ teaspoon sugar
• 1 teaspoon finely chopped shallot
• 1 teaspoon finely chopped flat-leaf parsley leaves
• Salt
• Mushroom Bruschetta
• ½ pound mixed mushrooms, such as oyster, shiitake and maitake
• Salt and freshly ground black pepper
• ¼ pound roughly chopped mustard greens (about 2 cups)
• Six ½-inch-thick slices multigrain bread, toasted
• 2 ounces crumbled feta cheese