Marinated Steak Sandwich with Cotija Mayo

For the Marinade: Core the jalapeño. Add the juiced limes, oil, jalapeño, garlic, brown sugar, soy sauce, apple cider vinegar, salt, and pepper to a food processor and blend until smooth. 

For the Cotija Mayo: Combine mayo, finely grated cotija, sour cream, squeezed lime, chili powder, and cayenne in a bowl and mix it all together. 

For the Sandwich: Marinate the steak for at least 30 minutes (not specified, but recommended). Slice the onion into rings or wedges and season lightly with oil, salt, and pepper. Grill the seasoned onion for 4-5 minutes per side until tender and slightly charred, then chop. Grill the marinated steak to your desired doneness (e.g., 4-6 minutes per side for medium-rare), then let it rest before slicing it thinly against the grain. Lightly grill or toast slices of the French bread. Finally, build your sandwich by layering the grilled steak, chopped onion, and a generous spread of Cotija Mayo on the grilled French bread, adding parsley, arugula, or cilantro as desired. Enjoy!