2 teaspoons butter
2 teaspoons olive oil
1/2 small onion, chopped
2 zucchini or yellow squash (12 ounces), thinly sliced
1/2 teaspoon dried basil
1/2 teaspoon salt
1/4 teaspoon ground black pepper
1/3 cup (1 ounce) shredded sharp provolone or swiss cheese
8 large eggs
1 tablespoon heavy cream or chicken broth