= For the potatoes =
1 1/2 pounds russet potatoes
1/4 cup half-and-half
2 ounces unsalted butter
3/4 teaspoon kosher salt
1/4 teaspoon freshly ground black pepper
1 egg yolk

= For the meat filling =
2 tablespoons canola oil
1 cup chopped onion
2 carrots, peeled and diced small
2 cloves garlic, minced
1 1/2 pounds ground lamb
1 teaspoon kosher salt
1/2 teaspoon freshly ground black pepper
2 tablespoons all-purpose flour
2 teaspoons tomato paste
1 cup chicken broth
1 teaspoon Worcestershire sauce
2 teaspoons freshly chopped rosemary leaves
1 teaspoon freshly chopped thyme leaves
1/2 cup fresh or frozen corn kernels
1/2 cup fresh or frozen English peas