Wash the potatoes. No need to peel them right now. If you have a pressure cooker, add 1 cup of water to the inner pot and place the potatoes on a rack or in a basket and pressure cook on high for 5 minutes with an immediate release of pressure. Or, you can boil a pot of water on the stove and cook the whole potatoes for 15-20 minutes or until a fork will just go into the potato.
Place the par cooked potatoes in a large bowl and refrigerate for at least 2 hours. The potatoes won't shred correctly if they are not cool enough.
Making & Freezing the Hash Browns
Prepare the 9x13 pan by lining it with parchment and spritzing about ½ Tablespoon of oil and then brushing the parchment with the oil.
Once the potatoes are cool enough, use a paring knife and remove the skin and any dark spots. Use a box grater or large hole cheese grater to grate the potatoes into a large bowl. I do not recommend using a food processor for this because the heat from the spinning blades can cause the potatoes to gum up from starch and not shred nicely.
Add the salt and cornstarch to the bowl of shredded potatoes and toss to evenly coat.
Dump the entire bowl of shredded potatoes onto the prepared parchment lined pan. Spread them out into an even layer and press them down so the potatoes compact together.
Freeze the tray for at least 2-3 hours so they are firm for cutting.
When they are firm, slide the parchment from the tray and onto your cutting board. Cut the frozen hash browns into the sizes or shapes you like. You can make them as small or big as you like, the size will not affect the cooking time since that is based on depth.
Transfer the parchment with cut hash browns back onto the tray and spritz the top with another ½ Tablespoon of oil. Freeze for at least 4 hours, but overnight is better.
If you are not cooking them right away, place the individually frozen hash browns into a freezer container or bag and freeze until you want to cook them. If you are ready to cook them, pick a cooking method below and proceed.
Air Fryer Instructions
Preheat the air fryer on the hottest temperature setting with the basket or tray in the air fryer for a full 10 minutes.
Place the frozen hash browns in a single layer in the air fryer and air fry on 375°F/190°C for 10 minutes. Flip and air fry another 5-10 minutes or until the hash browns are golden brown.
Remove from the air fryer and serve immediately or place on cooling rack until ready to serve.
Oven Instructions
Preheat the oven and the cooking tray on 450°F/230°C for 10 minutes. If you are using a convection oven, reduce the heat to 425°F/220°C. Spritz the cooking tray with oil or place a piece of parchment on it after it preheats.
Lay the frozen hash browns in a single layer and bake for 7 minutes. Flip and bake another 7-10 minutes or until they are golden brown on each side.
Serve immediately or place on a cooling rack until you are ready to serve.