Scrub and peel your potatoes, then slice them into 1/4-inch planks before cutting those into even fry-shaped strips. I like mine on the thinner side, but you can cut them thicker if you prefer a chunkier fry. Try to keep every piece a similar size so they all cook at the same rate.
Drop the cut potatoes into a bowl of ice water and let them sit for 30 minutes. This step pulls out excess surface starch, which is what actually gives you that crisp exterior later. Drain and rinse them two or three times until the water runs mostly clear.
Pat the potatoes completely dry with a clean kitchen towel or paper towels before frying. Any leftover moisture will cause the hot oil to splatter and can also make your fries soggy instead of crisp. I usually let them air-dry for a few extra minutes on the counter too.
Heat your oil to about 325°F and fry the potatoes in batches for 4 to 5 minutes, just until they're pale and soft but not browned. This first fry cooks the inside through so the second fry can focus purely on color and crunch. Lift them out and let them rest on a wire rack.
While the fries rest, melt the butter in a small saucepan and stir in the minced garlic, parsley, parmesan, salt, pepper, and oregano. Keep the heat low so the garlic turns fragrant without burning, since burnt garlic turns bitter fast. Set this mixture aside so it stays warm for tossing later.
Raise your oil temperature to 375°F and fry the potatoes again for 2 to 3 minutes until they turn deep golden brown. This second round is what creates that audible crunch on the outside while keeping the inside pillowy soft. Remove them straight onto a fresh paper-towel-lined rack to drain.
While the fries are still hot, transfer them to a large bowl and pour the warm garlic parmesan butter right over the top. Toss everything together so every fry gets an even coating, then finish with an extra sprinkle of parmesan if you like. Serve immediately while they're at their crispiest