Cook pasta shells according to package directions; drain and rinse with cold water. Drizzle with oil; toss to coat.
Place the lettuce in a 2-1/2-qt. glass serving or trifle bowl; top with pasta. Then layer on the egg slices. Sprinkle with salt and pepper.
Then layer with ham, salami and peas. In a bowl, mix mayonnaise, sour cream, green onions and mustard together. Spread over the top. Cover and refrigerate for several hours or overnight.
Just before serving, sprinkle with shredded cheese and parsley. Yield: 10 servings.