Sauté of Green Beans

• 1 large sweet onion (4 ounces), halved, finely sliced
• ¼ cup butter

In a large heavy frying pan, skillet, plat à sauter, etc., put the onion to cook gently in half the butter for from 15 to 20 minutes, stirring occasionally, until soft and yellowed, but not browned. At the same time gently stew the tomatoes, apart, in the remaining butter, with a pinch of salt and the oregano, tossing or stirring to prevent their sticking, until nearly dry, all the exces