Prep the potatoes. Shred the potatoes on the large holes of a box grater or with a food processor. Pop the shreds into a big bowl of cold water. Swish. The water will turn cloudy from starch. Drain, then repeat with fresh cold water. This quick rinse helps the hash browns crisp instead of steam.
Dry thoroughly. Spread the shreds on a clean kitchen towel and roll it up, then twist to squeeze out as much water as you can. This step matters. Damp potatoes fight browning.
Season the mixture. In a large bowl, toss the dried shreds with the onion, oil, salt, pepper, garlic powder, paprika, and cornstarch if using. It should look lightly glossy, not wet, and the seasonings should be evenly speckled throughout.
Preheat the air fryer. Heat to 380°F, about 193°C, for 3 to 5 minutes. While it warms up, decide your format. Loose shreds cook faster and get extra lacy edges. Patties are neater and good for stacking on breakfast sandwiches.
Shape if making patties. Scoop about 1/2 cup of the mixture per patty and press gently into thin rounds, about 1/2 inch thick. Not too compact. You still want some air in there for crisping.
Load the basket. Lightly spray the air fryer basket. Add the hash browns in a single layer. Avoid crowding. If you’re making a full batch, plan on two rounds. It’s worth it.
Air fry, then flip. Cook at 380°F for 8 to 10 minutes. Carefully flip with a thin spatula, then cook 6 to 8 minutes more until deep golden and crisp at the edges. If you want them even darker, give it 2 more minutes. Keep an eye on them near the end. Each air fryer runs a bit differently.
Season and serve. Sprinkle with a pinch more salt while hot. Add chives. Serve with eggs, avocado, or a little hot sauce. They’ll stay crisp for a few minutes as they cool, so no rush, but they’re best right away.