In a bowl, whisk together olive oil, lime juice, chili powder, smoked paprika, garlic powder, onion powder, salt, and black pepper. Add the flat iron steak to the marinade, ensuring it's well coated. Cover and refrigerate for at least 30 minutes, or up to 2 hours for maximum flavor.

Preheat your oven according to the instructions on the crinkle fries package. In a large bowl, toss the frozen fries with olive oil, chili powder, garlic powder, salt, and black pepper until evenly coated. Spread them in a single layer on a baking sheet.

Bake the seasoned crinkle fries according to package instructions, usually about 20-25 minutes, flipping halfway through until crispy and golden brown.

Preheat a grill or skillet over medium-high heat. Remove the steak from the marinade and let any excess drip off. Grill or sear the steak for about 4-5 minutes per side for medium-rare, or adjust cooking time to your desired doneness. Use a meat thermometer to check for an internal temperature of 130°F for medium-rare.

In a small bowl, combine mayonnaise, sour cream, minced garlic, lime juice, salt, and pepper. Mix until smooth and adjust seasoning to taste. Refrigerate until ready to serve.

Once the steak is cooked, let it rest for 5 minutes before slicing against the grain. Serve the sliced steak alongside the crispy seasoned crinkle fries. Drizzle with velvety garlic sauce and garnish with fresh cilantro and chopped parsley, if desired.