Step 1

*I recommend doing steps one and two concurrently to save time*Place the ground beef in a large walled skillet or saute pan and bring over medium-high heat. Cook, breaking the meat up into small pieces until browned. When the meat is cooked through, reduce the heat to medium and add the onions and carrots. Stir to combine and cook for 8-10 minutes, stirring occasionally, until the vegetables are soft. Sprinkle with salt and pepper to taste. Add the peas and stir together. Cook for another minute and then add the garlic, flour and tomato paste. Stir to combine and cook for a minute until the flour is blended. Add the broth, Worcestershire sauce, thyme and bay leaves and stir together. Bring to a simmer (this happened quickly for me) and reduce the heat to low. Simmer uncovered for 8-10 minutes, stirring occasionally, until the sauce has thickened and is coating the meat and vegetables. Remove the bay leaves and transfer the mixture into the bottom of a 9x13 casserole dish. Spread evenly and set aside.

Step 2

Pre-heat the oven to 425 degrees. Place the chopped potatoes at the bottom of a large pot and cover them in salted cold water. Place the pot on the stove, covered, and bring to a boil over high heat. Once the water is boiling, cook the potatoes for about 5 minutes and then drain the water. Spread the potatoes out on a clean, dry surface for about 5 minutes to allow the steam to escape. Transfer the potatoes to a mixing bowl and mash them until smooth. Add the butter, milk and about ¾ of the cheese and stir/mash until well combined. Add some salt and pepper to taste.

Step 3

Transfer the mashed potatoes to the casserole dish, spreading them in an even layer over top of the meat mixture. Sprinkle the remaining cheese on top. Place the dish in the oven and bake for about 30 minutes until the casserole is cooked through and the mashed potato peaks start to turn golden.