Fit a food processor with the grater blade.
Wash the potatoes and peel the onion.
Chop off the ends of the onion and cut it in half lengthwise.
Grate the potatoes and onion with the food processor on low.
Lay the potato-onion mixture out onto a thick layer of paper towel and pat dry. Lightly season with salt.
Melt 2 tablespoons of butter in an extra large skillet (we use a 12") and flatten the potato mixture into the bottom of the skillet. Season lightly with salt and pepper.
Cook on high heat for 5-10 minutes or until you see a layer of brown and crispy potatoes.
Add two more tablespoons of butter to the top of the hash browns and then gently flip them in secitons with a large spatula.
Season again with salt and pepper, if desired.
Continue to cook over high heat for an additional 10 minutes.
If needed, lightly "chop" potatoes with your spatula to mix them up a bit and continue flipping in intervals of 5 minutes until you achieve your desired level of crispiness.
Serve immediately and enjoy!