Preheat oven to 400℉.
To a large pot, add water, a heavy pinch of salt, and potatoes. Bring the water to a boil and cook for 20-25 minutes until soft. Drain and set aside.
Meanwhile, preheat a large pan to medium heat, and once hot, add 1 tbsp of oil. Add the carrots and onions and sauté for about 5-7 min until soft.
Add ground beef and cook for about 7 min until fully brown. Drain out any excess grease before adding in your seasoning.
Once the grease is drained, add dried rosemary, dried thyme, garlic powder, salt, and pepper. Mix well.
Add the tomato paste, chicken stock, and Worcestershire sauce to the meat mixture. Mix well and simmer for a few minutes to let the flavors come together.
Place the drained potatoes back in the pot and add a splash of cream and the butter and smash. Then add salt, pepper, garlic powder, and some dried thyme. Taste it and add more seasoning as necessary.
Finally, add the meat mixture to a baking dish, followed by the finished potatoes on top and spread evenly. I topped mine with some freshly grated sharp cheddar cheese and some more dried thyme.
Place in the oven for about 15-20 min until the cheese has melted and starts to look golden brown. Broil for 1-2 minutes at the end. Serve immediately and enjoy!!