- Toast and deseed the chiles. Soak in warm water (just covering chiles) for 10 minutes.
- Remove the chiles, reserving the chile-soaking water, and place into a blender with garlic, rosemary, and cilantro.
- Turn on the blender and slowly pour in the oil, followed by 1½ ounces reserved chile-soaking water and lime juice. Puree until completely smooth.
- Pour ⅓ of the marinade into a shallow dish. Arrange steak in a single layer and cover with another ⅓ marinade. Let sit 30−45 minutes.
- Heat a grill to medium high. Clean and lightly oil hot grill.
- Remove steak from marinade, shaking off excess, and season with salt and pepper.
- Grill steak until browned, 2−4 minutes per side for medium rare. Transfer to a cutting board and let rest 5 minutes before thinly slicing against the grain.
- Season reserved marinade with salt and pepper and serve with sliced steak. Garnish with shaved radish and roasted nopales.