Place the thinly sliced onions into a bowl and pour the milk over them, ensuring they are fully submerged. Let them soak for about five minutes to soften and absorb moisture.

In a separate bowl, mix together the flour, white pepper, garlic powder, onion powder, and salt until well combined. Take a handful of the soaked onions, allowing excess milk to drain off, and toss them into the flour mixture. Coat them evenly, then shake off any excess. Repeat the process, working in small batches to prevent clumping.

Heat a generous amount of vegetable oil in a deep skillet or fryer over medium-high heat. Once the oil reaches the right temperature, carefully drop in the coated onion slices in small batches. Stir occasionally to ensure even frying. Cook for about 2 to 3 minutes, or until the onions turn golden brown and crispy.

Using a slotted spoon, remove the fried onions and place them on a paper towel-lined plate to drain excess oil. While still warm, sprinkle with additional salt if desired. Store in an airtight container to maintain crispness. Serve immediately or use as a topping for various dishes.