1 lg. white onion
12-15 lg. fresh mushrooms
Salt & lemon juice
1 1/2 lb. cold roast beef, sliced thin
1/4 c. red wine vinegar
1 tsp. brown prepared mustard
Pinch each dried marjoram, chervil & crumbled ground pepper
1/2 c. salad oil
2 tbsp. chopped parsley

Peel onion, slice thinly and separate into rings. Rinse mushrooms and drop into boiling water. Add pinch of salt, few drops of lemon juice. Remove mushrooms immediately; blot dry on paper towels and slice lengthwise (thick). Drop onion rings into boiling water; remove immediately. Drain arrange meat, onion and mushrooms on serving platter.

Blend vinegar into mustard, stir in herbs, salt and pepper to taste. Gradually blend in oil. Pour over platter, arrange meat. Cover with saran film and chill for several hours. Baste occasionally.