Heat oil in skillet and add in onion, basil, garlic and
rosemary. Saute about
3 minutes. Transfer
to a bowl, mix in shrimp, bread crumbs, cheese and mayonnaise.
Season with salt and pepper
Arrange mushrooms, rounded side down, on an oiled baking
sheet. Mound shrimp filling in mushrooms, pressing filling to
Bake at 350 for 30-35 minutes.