To make this recipe, start by preparing your fries according to the package instructions, whether that's in the oven or the air fryer. Once they're crispy and golden, set them aside while you work on everything else.
Next, make the mango chimichurri. Add the finely diced mango, olive oil, chopped cilantro, chopped parsley, minced garlic, lemon juice, oregano, red pepper flakes, salt, and black pepper to a small bowl.
Stir everything together until well combined, then give it a taste and adjust the seasoning as needed. Set it aside to let the flavors meld while you cook the steak.
Now for the steak. Season it generously on both sides with salt and pepper. Heat a cast-iron skillet over medium-high heat, and let it get extremely hot before adding the steak. Once it's in the pan, resist the urge to move it — let it sear undisturbed for three minutes, then flip and cook for another three minutes on the other side.
Remove the steak from the heat and let it rest for a full 10 minutes before cutting it into cubes. (That rest is important — it keeps all those juices locked in.)
Finally, assemble your plates. Start with a base of fries, pile the cubed steak on top, and spoon that gorgeous mango chimichurri over everything. Serve right away and enjoy!