Shepherd's Pie

Ingredients
4 tablespoons salted butter
1 pound ground lamb
1/3 pound ground beef
1 cup chopped yellow onions
2 carrots, chopped
1 1/2 teaspoons salt
1 teaspoon ground black pepper
4 ounces button mushrooms, cleaned and sliced
1 bay leaf
2 tablespoons all-purpose flour
1 tablespoon tomato paste
1 1/2 cups beef stock or broth
1 teaspoon Worcestershire sauce
1 1/2-2 pounds potatoes, skins peeled, and cut into chunks
1/2 cup whole milk
1/2 cup white cheddar, grated

Preheat the oven to 400 degrees F.

Lightly grease a 6-cup baking dish and set aside.

Melt 2 tablespoons of the butter in a large saute pan over medium high heat. Add the lamb and beef, stirring to crumble, and cook until starting to brown, about 3 minutes. Add the onions, carrots, 3/4 teaspoon salt, and 1/2 teaspoon of the pepper, and cook, stirring, for 2 minutes. Add the mushrooms and bay leaf, and cook, stirring, until their liquid is almost all gone, about 4 minutes. Add the tomato paste and cook, stirring, until starting to color, about 1 to 2 minutes. Add the flour and cook, stirring, for 1 minute. Gradually add the stock and Worcestershire sauce, and bring to a boil. Reduce the heat to medium-low, cover, and simmer until thickened, about 20 to 25 minutes.

Meanwhile, place the potatoes in a medium pot and cover with salted water by 1-inch. Bring to a boil and cook until tender, about 10 minutes. Drain in a colander and put in a bowl. Add 2 tablespoons of butter, 3/4 teaspoon of salt, 1/2 teaspoon of pepper and whole milk. Combine with a hand mixer to incorporate.

Remove the pot with the meat from the heat. Remove the bay leaf. Spoon into the prepared dish and top with the mashed potatoes, smoothing the top. Sprinkle the cheese over the top and bake until browned and bubbly on top, 10 to 15 minutes. Remove from the oven and serve immediately.