Step 1

Preheat oven to 375 degrees Fahrenheit. Set two pots of water to boil. Place the potatoes into one and the carrots into the other. Boil both the potatoes and the carrots until soft; drain. Save 2/3 cup of the potato water for later.

Step 2

In a large bowl, add potatoes, butter, cheddar cheese and 1/2 teaspoon salt. Mash together with the back of a fork. Set aside.

Step 3

In a separate bowl, mash the carrots with the back of a fork. Set aside.

Step 4

Put a large saute pan on medium-high heat. Add oil. When oil becomes hot, add onions and garlic. Adjust heat as needed. Cook until onions are soft and translucent.

Step 5

Add ground beef to the pan with the remaining teaspoon of salt and pepper to taste. Cook until all the meat has browned. Add the 2/3 cup of potato water you set aside earlier, as well as the tomato paste. Mix well. Simmer for 10 minutes, or until thickened.

Step 6

Spread the beef mixture evenly in the bottom of a baking dish. Spread the mashed carrots over the beef. Finish with a layer of the mashed potatoes over the carrots. Bake the casserole for 30 minutes, or until the mashed potatoes are just browned.

Step 7

Cool for 5 minutes, then serve.