This is inspired by Serious Eats tip of alkalizing the cooking water to change the texture just like we do with pho noodles. Baking soda changes things. Note: MORE IS NOT BETTER. We're not adding oil to ours like they do. The fat you eat is the fat you wear. We can get plenty of flavor and crunch without that useless ingredient.
Use a skillet the size you need for the amount of potato cubes you're cooking to make one layer.
Peel and cube your potatoes (I use russet for this but any high starch potato will work, we need starch here) then place them in the skillet and turn it on to medium low heat. Add in your favorite no salt seasoning like Mrs. Dash, this cooking process will allow the seasoning to rehydrate and cook into the potatoes. Add enough water to cover halfway and 1/8 tsp baking soda. Allow to simmer until water is evaporated stirring occasionally. This will take about 20 minutes.
As cooking time comes to an end really rough up the potatoes with a wooden spoon so they get a nice pasty outer coating. All that starch is going to crisp up in the next step. I highly recommend cooling them off first before moving onto the roasting step. I may cook them in the pan first then go run errands or go for a walk then crisp them up when I get back.
I use an air fryer for the next step but you can use your oven set to 400 and parchment paper. I don't know oven cooking time so you will have to watch it until it's a desired brown-ness.
Turn the starchy cooked potatoes into your air fryer basket and cook at 400 (or 390 if your fryer only goes that high) for about 15-19 minutes. Shake or stir once 10 minutes in.
Eat immediately. Serve with your favorite no fat sauce like ketchup, bbq sauce, mustard etc.