Vegetables Glazed With Balsamic Vinegar

Ingredients
2 tablespoons olive oil
1 red bell pepper, cut into 1/4-inch-wide strips
1 yellow bell pepper, cut into 1/4-inch-wide strips
1 small onion, thinly sliced
2 zucchini, trimmed, cut crosswise into 1/2-inch-thick rounds
2 yellow summer squash, trimmed, cut crosswise into 1/2-inch-thick rounds
2 tablespoons balsamic vinegar

Directions
Heat oil in heavy large nonstick skillet over medium-high heat. Add peppers and onion. Sauté until beginning to soften, about 4 minutes. Add zucchini and yellow squash and sauté until tender, about 8 minutes. Add vinegar to skillet and boil until liquid is reduced to glaze and coats vegetables, about 2 minutes. Season to taste with salt and pepper. Transfer to platter and serve.