FILLING:

1 c. mushrooms
1/2 c. chopped onion
2 tbsp. butter
1/3 c. sour cream

MEAT LOAF:

1 1/2 lbs. ground beef
3/4 c. rolled oats
2 eggs
2 tsp. salt
1/4 tsp. pepper
1 tsp. Worcestershire sauce
2/3 c. milk

Lightly brown the mushrooms and onion in butter. Remove from heat and mix in sour cream. Combine all meat loaf ingredients. Place half in shallow pan. Form an oval base with a "well" in the center. Spoon in the filling and cover with remaining meat loaf mixture, sealing top and bottom. Bake at 350 degrees for 1 hour.