Veggie Salad - cooking recipe

Ingredients

1 small onion, chopped
1 medium green pepper, chopped
1 medium yellow squash, chopped
1 medium red bell pepper, chopped
1 medium zucchini, sliced
1 8-oz pkg mushrooms, sliced
1 c olive oil
1/2 c balsamic vinegar
2 T butter or margarine

Preparation

In saucepan melt butter and saute vegetables lightly-don't overcook.
Remove from heat and cool completely, transfer to bowl. Blend together oil and vinegar and pour over vegetables, salt and pepper to taste.
Cover and refrigerate overnight.