Calling rajas a versatile dish might be an understatement; these strips of chilies and onion in cream become a main dish as a filling for tacos, make a flavorful side dish for grilled meats, work as a mix-in ingredient for scrambled eggs and the like, and, when used sparingly, serve as a condiment. Relatively mild poblano chilies make the perfect choice for a dish like this, in which the flavor of the peppers becomes more important than their spiciness. Make a double batch because you will find many ways to enjoy rajas once you have them on hand.