• Preheat oven to 400℉. Gather your ingredients so that you have everything close at hand on the counter or table.

Prepare the Ingredients

• Peel and dice 2 large carrots. Dice 1 cup sweet onion. Mince 2 cloves garlic.
• Using a handheld grater, shred 1 cup cheddar cheese.
• Heat 3 cups prepared mashed potatoes (leftover) in the microwave until warm.

Make the Meat Layer

• In a large cast iron skillet, brown 1.5 pounds ground beef over medium-high heat for about 8-10 minutes. Season with 1/2 teaspoon kosher salt and 1/2 teaspoon freshly ground black pepper.
• Using a wooden spoon or spurtle, stir in the diced carrots, sweet onion, and minced garlic. Sauté for 3-4 minutes until the onion is tender.
• Stir in 2 tablespoons Worcestershire sauce and 1 1/2 teaspoons dried thyme.
• Create a space in the center by pushing the hamburger mixture to the edges. Add 2 tablespoons tomato paste to the center and cook until slightly darkened, 1-2 minutes. Then stir the paste into the rest of the dish.
• Pour in 1 cup dark beer and stir to combine. Cook for 4-5 minutes until reduced.
• Add 1 cup frozen peas, along with 1 cup beef broth. Bring to a boil, then reduce heat to a simmer. Continue to cook for another 12-15 minutes, until the broth has reduced.

Assemble the Cottage Pie

• To assemble the layers, add spoonfuls of the leftover mashed potatoes to the top of the meat mixture.
• Sprinkle the tops of the potato mounds with grated cheddar cheese.
• Bake in preheated oven until the mixture bubbles around the edges about 25-30 minutes. Remove from heat and allow to rest 5-7 minutes before serving. Serves 6-8.