Easy Shepherd's Pie

Bahan-bahan (6 porsi)

• 1 ½ pounds russet potatoes
• 3 tablespoons unsalted butter (diced)
• ¼ cup freshly grated Parmesan cheese
• ½ teaspoon kosher salt
• ¼ teaspoon ground black pepper
• ¼ cup milk (or half-and-half)
• 1 large egg yolk
• 1 tablespoon extra-virgin olive oil
• 1 yellow onion (chopped)
• 2 g arlic cloves (minced)
• 1 tablespoon tomato paste
• 1 pound lean ground beef or ground lamb
• ½ teaspoon kosher salt
• ¼ teaspoon ground black pepper
• 2 tablespoons all-purpose flour
• 1 cup less sodium beef broth or chicken broth
• 1 tablespoon Worcestershire sauce
• 2 sprigs fresh thyme
• 1 dried bay leaf
• 1 (10- to 12-ounce) bag frozen peas and carrots (no need to thaw)