Vegetarian Shepherd's Pie Recipe | Epicurious

Ingredients

• 10 ounces pearl onions (about 2 1/4 cups)
• 9 tablespoon olive oil, divided
• 1 1/2 pounds seitan, sliced 1/4 inch thick and patted dry
• 3 medium leeks (white and pale green parts only), halved lengthwise, sliced 1/2 inch thick, and washed
• 3 garlic cloves, chopped
• 1 pound cremini mushrooms, trimmed and quartered
• 3/4 pound carrots (about 4 medium), cut into 3/4-inch-thick pieces
• 3/4 pound parsnips (about 4 medium), cut into 3/4-inch-thick pieces
• 2 tablespoons thyme leaves
• 1 tablespoon chopped rosemary
• 1 (750-ml) bottle full-bodied red wine such as Burgundy or Côtes du Rhône
• 3 tablespoons unsalted butter, softened
• 3 tablespoons all-purpose flour
• 3 1/2 cups hot rich vegetable stock
• 1/2 cup chopped flat-leaf parsley
• 2 1/2 pounds Yukon Gold potatoes
• 3/4 pound celery root, peeled and cut into 1-inch pieces
• 1/2 stick unsalted butter
• 1/2 cup whole milk
• 1/2 cup heavy cream
• Equipment: a 3-quart shallow (2-inch-deep) flameproof baking dish; a potato ricer or a food mill fitted with medium disk
• a potato ricer or a food mill fitted with medium disk