Begin by cutting the large russet potatoes crosswise using a mandoline for thin, even slices. Soak the slices in a bowl of cold water for 1 hour to remove excess starch.

While the potato slices soak, combine dark brown sugar, kosher salt, garlic powder, chili powder, and paprika in a small bowl. Mix these ingredients thoroughly to ensure an even distribution of flavors.

After the soaking time, drain the potato slices and lay them out on paper towels. Blot the slices gently for about 30 minutes to remove any excess moisture.

In a Dutch oven, pour in enough peanut or vegetable oil to reach 2-3 inches deep, and heat it to 375°F. Monitor the temperature with a thermometer.

Once the oil is hot, carefully fry the potato slices in small batches for 2-4 minutes until golden brown and crisp. Place them on paper towels to drain excess oil.

While the chips are still warm, transfer them to a clean paper bag. Sprinkle the spice mixture generously over the chips and shake the bag vigorously to coat them evenly.

Let the chips cool completely on a lined surface before storing in an airtight container.