Combine the marinade ingredients in a bag. Add the steak, cover and refrigerate for 4 hours or overnight.
When you’re ready to cook the meat, preheat the grill to medium-high heat. Grill the steak for 3 minutes on each side or until the steak reaches 125°F for medium rare, or more if you prefer. Transfer the meat to a plate, cover with foil, and set aside.
Cook the fries according to the instructions on the package.
While the fries are cooking, melt the butter into a saucepan over medium heat. Once melted, add the flour and whisk it into the butter. Cook for 1 minute. Slowly pour in the milk, whisking constantly, until the sauce has thickened.
Add about half of the cheese and whisk until smooth. Then add the remaining cheese and whisk until smooth. Remove from the heat.
Cut the steak against the grain into bite-size pieces.
When the fries are done, spread them on a sheet pan or serving platter.
Drizzle on some cheese sauce and top with steak. Then add the rest of the cheese sauce.
Dress them up with avocado, pico de gallo, sour cream, green onions, and jalapeño.