Serves 6 as a side dish. You can make this a day ahead and let it mellow in the refrigerator.
3 Tbsp extra virgin olive oil
1 medium onion, sliced
2 ribs celery, sliced on an angle
1 large clove garlic, sliced
1 large zucchini, sliced on an angle
1 yellow squash, sliced on an angle
1 green pepper, sliced
1 red pepper, sliced
1 yellow pepper, sliced
10 mushrooms, sliced
1/2 can small pitted black olives
1 Tbsp fresh chopped thyme or oregano
Black pepper to taste
Rice vinegar, 1/4 cup or more
A drop or two of honey (optional)
In a large nonstick frying pan, heat the olive oil. Add onion and saute briefly. Add garlic, celery, zucchini and peppers, and continue to saute for 2-3 minutes. Add remaining ingredients, and cook until all vegetables are just tender.
You might want to add more rice vinegar to taste — basically, you're making a cooked vinaigrette dressing.
Serve at room temperature, or warm, or cold.