If a recipe calls for onions and you're in a time-crunch, you can use frozen onions instead if you have them on hand. The dish won't be as flavorful, but the preparation will go more quickly. You don't have to thaw the onions before you use them. Cook them until they're just soft, about two minutes. Then you can add herbs and other seasonings if you want to.
Try this Kitchen Shortcut with Seared Tuna Sandwhich with Balsomic Onions.