Blanch the mushroom caps in salted boiling water. Drain the mushrooms. Preheat oven to 400 degrees F. Bake the mushrooms for 15 minutes.
Stuff mushrooms generously with stuffing.
Drizzle with olive oil. On each of 4 salad plates, make a bed of the salad and arrange 4 mushrooms on top. Drizzle any pan juices and melted fat over the plates and squeeze a little lemon juice over each serving. Blanche the pappardelle until al dente and drain. Begin by adding the capers and cook until slightly crisp.