Boil potatoes for 15 minutes. Drain and mash potatoes with a potato masher. Add water, 1 tablespoon of the butter, 1 teaspoon of salt and a dash of pepper. Whip with a spoon until fluffy and set aside.
Heat oil in a skillet. Add onion and carrot and cook on low heat for 15 minutes. Add ground beef and stir over a medium heat, breaking up meat with a spatula for 5 more minutes. Drain beef mixture. Then add flour for 2 more minutes. Pour in bouillon, thyme, 1 teaspoon of salt, and nutmeg. Simmer until thickened for 5 minutes.
Spoon into a 9-inch pie plate. Spread the mashed potatoes over the top. Scatter the remaining 2 tablespoons of butter around the potatoes. Bake for 30 minutes. Serve and enjoy.
Notes
Need to make it dairy-free? No problem. Instead of butter, use a dairy-free butter substitute like Earth Balance.
If you can tolerate dairy, you can prepare your mashed potatoes with milk or half and half instead of water.
I love to make homemade mashed potatoes, but if you want to save time Betty Crocker Potato Buds are gluten free and ready in 5 minutes.