Preheat oven to 375°F.

Heat oil in a large nonstick frying pan. Saute onion and carrots over low heat for 5-6 minutes.

Add ground beef and cook for 10 minutes or until browned; drain. Stir in stock, cover and reduce heat. Simmer for 15 minutes, stirring occasionally. Season to taste with salt and pepper.

Place potatoes in a pan and cover with cold water. Bring to a boil and simmer for 15 minutes, or until potatoes are tender. Drain, return to the pan and mash, beating in the horseradish sauce, milk and parsley.

Transfer meat to 1 1/2-qt baking dish, draining off some broth if mixture seems to soupy. Spoon mashed potatoes over meat to cover; use a fork to score the top. Bake for 30-35 minutes, until potatoes begin to brown.