Method

• Day 1
• Fill large bowl with cold water. Slice potatoes lengthwise on thinnest setting with mandoline and put in water while you work.
• Preheat oven to 250F / 120C. Line 9×5 loaf pan with baking paper allowing some to hang over all 4 sides.
• Pour melted tallow into another large bowl. Working in batches, dry potatoes in clean towel and move to bowl with tallow.
• Layer potatoes in loaf pan, slice by slice until you have built up about 3/4 of the pan. Do your best to keep the layers as even as possible.
• Cover the top with a folded piece of baking paper that fits neatly inside the pan. Using another 9×5 loaf pan, press down firmly and remove.
• Wrap in aluminum foil, pressing around the top to seal. Place on 2 stacked sheet pans to insulate and cook for 3 hours.
• Once cooked, remove from oven and leave wrapped. Put the 2nd loaf pan on top and place heavy cans or weights inside and allow to cool for 1 hour.
• Put in refrigerator, with weights, and chill for 24 hours.
• Day 2
• When ready to finish, remove weights and wrapping. Turn upside down on cutting board and use a blow torch around all sides to loosen potatoes.
• Once they have dropped, remove pan and remaining baking paper. Cut into pieces appropriate for your needs and place on sheet pan. Put pieces back in refrigerator until ready to fry.
• Heat oil to 375F / 190C and oven to 125F / 50C.
• Fry in batches until golden brown. Be mindful to allow oil to get back up to temp before each round.
• Immediately after removing from oil, place on sheet pan lined with paper towels, sprinkle with sea salt and put in oven to keep warm.