Peel the russet potatoes (optional — leaving the skin adds texture). Cut into 1/3-inch (8 mm) sticks: halve the potato lengthwise, then slice each half into 1/3-inch slabs and stack to cut into sticks. Aim for uniform size so they cook evenly. You should end up with roughly 4 cups of cut fries.

Soak to remove starch

Place cut potatoes in a large bowl and cover with 8 cups cold water. Add 1 tablespoon coarse kosher salt and stir. Soak for 30 minutes to 1 hour (30 minutes is sufficient for moderate starch removal; 1 hour yields crisper fries).

Rinse and dry

After soaking, drain the potatoes and rinse under cold running water until the water runs clear. Spread them in a single layer on clean kitchen towels or paper towels and pat thoroughly dry. Excess moisture will cause oil to splatter and prevents crisping.

Frying oil

Heat oil

Pour 3 cups neutral oil into a heavy-bottomed pot or Dutch oven (use enough to give a 2-3 inch depth but do not overfill the pot). Attach a thermometer and heat oil over medium-high until it reaches 325°F (163°C) for the first blanching fry.

First fry (blanch)

Working in batches of about 1 to 1 1/2 cups of cut fries (do not crowd), add fries to the oil and cook for 4 to 5 minutes until they are soft and pale golden but not browned. Use a slotted spoon to transfer fries to a wire rack set over a baking sheet. Let drain and cool for 5–10 minutes. Repeat with remaining batches.

Raise oil temperature

After all batches are blanched and cooled, increase oil heat and bring to 375°F (190°C) for the final crisping fry.

Second fry (crisp)

Working in similar-size batches, fry the blanched fries for 2 to 3 minutes until golden-brown and crisp. Remove with a slotted spoon and transfer directly to a paper-towel-lined tray or a wire rack. Immediately sprinkle each batch lightly with flaky finishing salt (about a pinch each) while they are hot so the salt adheres. Let any excess oil drain for a minute.

Crisp finishing seasoning

Prepare seasoning mix

While fries are frying, combine 1 teaspoon smoked paprika, 1 teaspoon ground black pepper, 1 teaspoon garlic powder, and 1/2 teaspoon onion powder in a small bowl. Stir to blend.

Toss fries with seasoning

Place hot, drained fries in a large bowl or leave on the wire rack and sprinkle the seasoning mix evenly over them. Toss gently so the spices coat the fries without breaking them. Sprinkle the chopped parsley over the fries and gently toss again to combine. If using grated Parmesan, add 2 tablespoons now and toss lightly so it adheres.

La Boca finishing sauces & garnish

Make La Boca sauce

In a small bowl whisk together 1/2 cup mayonnaise, 1 tablespoon sriracha (or preferred hot sauce), 1 tablespoon lime juice, and 1/2 teaspoon Dijon mustard until smooth and slightly loose. Taste and adjust heat or acidity as desired. This creamy, tangy sauce is the signature pairing for these fries.

Serve

Pile fries on a large platter or individual plates. Drizzle some La Boca sauce over the fries or serve it on the side for dipping. Finish with a light sprinkle of flaky finishing salt (about 1/2 teaspoon total) and a few more pinches of fresh parsley for color. Serve immediately while hot and crisp.