Chicken and Mushroom Shepherds Pie with Parsnip Mash

Name: Chicken and Mushroom Shepherd's Pie with Parsnip Mash
Ingredients: 1/4 cup dried porcini mushrooms (1/4 ounce); 1/2 cup boiling water; 1 1/2 pounds skinless, boneless chicken thighs, cut into 1-inch pieces; Kosher salt and freshly ground pepper; 2 tablespoons extra-virgin olive oil; 6 tablespoons unsalted butter; 3/4 pound white mushrooms, quartered; 1 medium onion, cut into 1/4-inch dice; 2 medium carrots, cut into 1/2-inch dice; 1 celery rib, cut into 1/4-inch dice; 3 tablespoons all-purpose flour; 1 1/2 cups chicken stock or low-sodium broth; 2 thyme sprigs; 1 pound Yukon Gold potatoes, peeled and cut into 1-inch dice; 1 pound parsnips, peeled and cut into 1-inch dice