Barbecued Meat Loaf with Shiitake Mushrooms

Meat loaf

• 12 large shiitake mushrooms, about 6 ounces total
• Extra-virgin olive oil
• 1 cup soft bread crumbs, preferably slightly stale
• ¼ cup whole milk
• 2 pounds ground chuck (80% lean)
• 1 egg, lightly beaten
• 2 tablespoons Dijon mustard
• 1 tablespoon Worcestershire sauce
• 1 tablespoon minced garlic
• 1 teaspoon dried thyme
• 1 teaspoon kosher salt
• ½ teaspoon finely ground fresh black pepper

• ⅓ cup store-bought barbecue sauce