Here's a wonderful dish that is rich and savory...and easy to make as a one-pot meal. I especially like to make this when I have leftover mashed potatoes in my fridge.
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 the carrots. Dice the sweet onion. Mince the garlic cloves.
Using a handheld grater, shred the cheddar cheese.
Heat the leftover mashed potatoes in the microwave until warm.
Make the Meat Layer
In a large cast iron skillet, brown the ground beef over medium-high heat for about 8-10 minutes. Season with kosher salt and freshly ground black pepper.
Using a wooden spoon or spurtle, stir in the diced carrots, sweet onion, and minced garlic. Saute for 3-4 minutes until the onion is tender.
Stir in Worcestershire sauce and dried thyme.
Create a space in the center by pushing the hamburger mixture to the edges. Add the 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 the stout beer and stir to combine. Cook for 4-5 minutes until reduced.
Add frozen peas, along with the 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.