* Anillos de cebolla dorados rebozados: This is a very literal translation and probably the most common and easily understood option. "Rebozados" means battered.
* Anillos de cebolla fritos dorados y empanados: This option uses "empanados," which implies a breadcrumb coating, which is often used in addition to or instead of a batter. If your onion rings have a breadcrumb coating, this is a better choice. "Fritos" clarifies that they're fried.
* Anillos de cebolla crujientes dorados: This focuses on the texture ("crujientes" means crispy) and golden color. This option omits the mention of battering but still conveys the idea.
The best choice depends on the specific preparation. If it's a simple batter, the first option is ideal. If it has a breadcrumb coating, the second is better. If you want to emphasize the crispness, the third is a good choice.