Ingredients 
4 Large yellow onions (9 to 11 oz. ea.)
2 tsp. Olive oil
1 lb. Yellow summer squash, cut into julienne strips
1/2 lb. Mushrooms, sliced
3 Stalks Celery, sliced
1 Red bell pepper, sliced
3 Large Cloves Garlic, thinly sliced
2 Medium tomatoes, cubed
1/3 Cup Parsley, minced
1/2 tsp. Tarragon
1 Cup White wine
Method
Peel onions; cut flat slice off base of each onion so they will stand upright. Hollow them out, leaving 1/2-inch shells. Chop onion from centers. Place onion shells in large skillet, add 1-inch water, cover and bring to boil. Simmer gently for 25 minutes or until soft. Remove from skillet with slotted spoon and drain.
Empty skillet; add oil and heat. Add chopped onion, squash, mushrooms, celery, red pepper and garlic; sauté over medium heat until tender-crisp, about 6 to 8 minutes.
Add tomatoes, parsley, tarragon and wine and cook 2 minutes longer. Nestle onion shells into pan and fill with vegetable mixture. Yield: 4 Servings.
Recipe and photo courtesy of the National Onion Association.