Italian Stuffed Portabellos

This recipe is courtesy of the Moosewood Restaurant "New Classics" cookbook. It is really one of me and my husband's favorite cookbooks.
I have been seeing a lot of mushrooms at the downtown Farmers Market (although I think they come from Oregon - Utah doesn't have the best mushroom climate).
The mushrooms can easily be served on a bed of pasta, a side of polenta, or on toasted ciabatta bread.

Ingredients:
4 large portabello mushrooms
3 TBS. olive oil
1 cup minced yellow onion (can get at farmers market)
3 large garlic cloves minced or pressed (can get at farmers market)
2/3 cup minced red bell pepper (will soon be available at farmers market)
3 TBS. chopped fresh basil (can get at farmers market)
2/3 cup ricotta cheese
1 cup grated mozzarella cheese (can most likely get at farmers market)
1/4 cup grated parmesan cheese (can most likely get at farmers market)
1/4 tsp. salt
2 TBS. bread crumbs

Directions:
1. Preheat oven to 400 degrees. Lightly oil a baking dish (9x13 or so).
2. Carefully brush or wipe off any soil from the mushrooms. Twist off the stems and discard.
3. In a skillet, warm 2 TBS. of the olive oil and saute the onions for about 5 minutes, until they begin to soften. Add the garlic and red peppers and saute for 5 minutes more. Remove from heat and set aside.
4. In a bowl, mix together the basil, ricotta cheese, mozzarella, parmesan, salt and bread crumbs. Stir the sauteed vegetables into the cheese mixture.
5. Brush the portabellos with the remaining TBS. of oil and place them gill side up in the prepared baking dish. Mound cheese mixture in each.
6. Back uncovered for 20-25 minutes, until the mushrooms release their juices and the cheese is melted. Serve hot.