Using a box grater, grate the potatoes and transfer into a large bowl (you want to move quickly to avoid any oxidation). Cover with water, agitate to rinse off any excess starch, drain, and dump the potatoes on a clean towel.

Gather up the sides of the towel and wring out the excess liquid.

Into a large, 7-8 quart (6.6-7.5L) heavy bottom pot or Dutch oven, add the duck fat and the grated potatoes - off the heat - and mix together. Place over medium heat and cook, stirring occasionally, until a thermometer reads 215℉/ 102℃.

Immediately and carefully strain the potatoes, reserving the fat.

Pour the potatoes out onto a rimmed baking sheet and spread them out. Generously season, to taste, with salt and mix to incorporate. Cool to room temperature, or until cool to the touch.

Line a baking sheet with wax paper. Grab handfuls of the potatoes and shape (by hand) into the classic hash brown oval shape (2.5”/6cm wide x 3.5”/9cm long, & ¾”/19mm thick). Pat and press the potatoes tightly together to hold their shape.

Cover with plastic wrap and refrigerate overnight.

Fill a 7-8 quart (6.6-7.5L) heavy bottomed pot or Dutch oven with the reserved duck fat and heat over medium to 355℉ (180℃). Line a baking sheet with a cooling rack and place that next to the pot.

Fry the cold hash browns, no more than 2 at a time, in the hot duck fat for 3-6 minutes, until evenly golden brown and crispy. Transfer to the cooling rack and repeat with the remaining hash browns.

Season with salt, to taste and serve with the condiment of your choice.

Whisk all the ingredients for Herb Mayo together in a bowl and use immediately or refrigerate until ready to serve.

Whisk all the ingredients for Spicy Ketchup together in a bowl and use immediately or refrigerate until ready to serve.