Gently immerse the onions in a pot of boiling water seasoned with a pinch of salt, allowing them to cook until tender, typically ranging from 30 to 45 minutes depending on their size. Once cooked to perfection, carefully drain the onions and proceed to gracefully cloak them in either a white or brown sauce, ensuring every inch is enveloped in flavorful decadence. This meticulous preparation lends itself to a delightful presentation when the dish is ultimately served.