Heat oil over medium-high heat in a cast iron skillet. Brown ground beef in the skillet for about 5 minutes.
Stir in chopped carrots, onion, celery stalks, and minced garlic to the ground beef. Cover and continue cooking, stirring occasionally, for about 10 minutes, or until vegetables are tender.
Preheat oven to 350 F. Pour in tomato paste and vegetable broth in the skillet and stir everything. Season to taste with dried oregano, fresh thyme, salt and freshly ground pepper. Cover and simmer for a couple of minutes, until most of the juices have evaporated.
Remove from heat. Even out the vegetable mixture in the skillet, and spread out evenly the leftover mashed potatoes over it. If you are using a narrower baking dish, you might need less mashed potatoes. Make sure the mashed potato topping covers the vegetables.
Place in the preheated oven and bake for 15 minutes. If you wish, you can place the skillet/baking dish under the broiler for the last 4 minutes. Make sure to watch it closely as it can burn quickly.
Easy Skillet Shepherd's Pie
Amount Per Serving (441 g)
Calories 446Calories from Fat 119
% Daily Value*
Saturated Fat 4.1g21%
Polyunsaturated Fat 9.1g
* Percent Daily Values are based on a 2000 calorie diet.