Scrub the potatoes under cold running water to remove dirt. Do not peel unless you prefer peeled chips. Using a mandoline set to 1.5–2 mm (or a very sharp chef’s knife), slice the potatoes into uniformly thin rounds. Uniform thickness ensures even cooking.

Rinse and dry

Place the potato slices in a large bowl and cover with cold water. Swirl and drain, then repeat until the rinse water runs much clearer (2–3 times) to remove surface starch. For extra-crispy chips, let the slices soak in cold water for 30 minutes. Drain and spread the slices on clean kitchen towels or paper towels and pat thoroughly dry.

Optional cornstarch dusting

If using cornstarch, put the dried slices in a large bowl, sprinkle the cornstarch over them, and toss gently to coat each slice lightly. This creates an extra-crispy finish.

Frying

Heat oil

Pour the oil into a heavy-bottomed 4–5 quart pot or Dutch oven to a depth of about 2 inches (about 3–4 cups). Clip a deep-fry thermometer to the side and heat the oil over medium-high heat to 350°F (175°C).

Fry in batches

Working in small batches (about 6–8 slices at a time depending on your pot size — do not overcrowd), gently lower slices into the hot oil using a spider or slotted spoon. Fry, stirring gently, for 2–4 minutes, until the edges are golden and centers are still slightly pale. For very thin slices the time will be closer to 90–120 seconds; thicker slices will take longer. Remove chips with a slotted spoon and transfer to a paper towel–lined baking sheet to drain. Immediately sprinkle a portion of the fine sea salt and a light crack of black pepper over the hot chips.

Maintain temperature

Allow oil to return to 350°F between batches before adding the next set of slices. Continue until all slices are fried.

Seasoning and finishing

Flavor blends

While chips are still warm, toss them in a large bowl with your chosen flavor mix-ins. Example combinations: 1) Classic: just fine sea salt and black pepper. 2) Smoky Garlic: 1 tsp smoked paprika + 1 tsp garlic powder. 3) Parmesan Herb: 2 tbsp grated Parmesan + 1 tbsp chopped parsley. 4) Ranch: 1 tbsp ranch seasoning. Taste and adjust — add more salt or seasoning to taste.

Cool to crisp

Spread seasoned chips in a single layer on a baking sheet and let cool completely (about 10 minutes). As they cool they will crisp up further.

Assemble the bag

Portion into bags

Once chips are completely cool, portion them into small paper lunch bags if serving individually, or a larger bowl for sharing. If using bags, fold the top over or clip lightly. Garnish with a sprinkle of chopped parsley for presentation if desired.

Storage

Store any leftovers in an airtight container at room temperature for up to 2 days for best crispness. Avoid refrigerating (will become soft). Re-crisp in a 300°F (150°C) oven for 5–7 minutes if needed.