Shake Shack has taken the country by storm with its tasty, top-quality burgers and fries, and its latest menu offering—the crunchy, tangy fried Chick'n Shack sandwich—might be its most popular item yet! This blockbuster sandwich has made new fans out of eaters who aren't into burgers, but if you don't have a Shake Shack near you, don't worry. You can make a mouthwatering version at home that's just as tender and juicy, but a little healthier than the deep-fried Shack original. An overnight buttermilk marinade and super-seasoned batter make this sandwich something to crow about. Yes, it takes a little elbow grease, but it’s totally worth it.
The night before: Marinate the chicken and make the mayonnaise
Pound each chicken breast with a meat tenderizer to a fairly uniform 3/4-inch thickness. (This will help the chicken cook more evenly.) Cut each chicken breast in half to make 8 sandwich-sized cutlets.
Place the chicken in a gallon-size zip-top bag and pour the buttermilk and pickle brine over the chicken. Seal the bag and squeeze gently to evenly distribute the marinade around the chicken.
Refrigerate overnight or for up to 24 hours.
Make the buttermilk herb mayonnaise by whisking the mayonnaise with the buttermilk, chives, parsley, thyme, and pepper in a small bowl. Cover and refrigerate until ready to serve.
The next day: Cook the chicken and make the sandwiches
Preheat the oven to 375 degrees F. Place an oven-safe wire cooling rack on a rimmed baking sheet so that it fits comfortably.
Make your dry breading by whisking the flour, celery salt, pepper, and cayenne together in 1 large bowl.
In a separate bowl, make the batter by whisking the flour, cornstarch, baking powder, and salt together, then drizzle the water into the bowl while whisking until fully incorporated.
Drain the chicken and discard the marinade. Line a large baking sheet with paper towels and place the chicken on the sheet, patting each piece dry with additional paper towels.
Heat 1/2 cup canola oil in a high-sided, heavy-bottomed pan such as a Dutch oven or cast iron pan until a drop of batter flicked into the pan sizzles and browns.
Shallow-fry the chicken 2-3 pieces at a time as follows: Lightly dredge a piece of chicken in the flour, then submerge in the batter. Let excess batter drip off the chicken, then return to the flour for a final coating. This will be a messy process, but well worth it for the crunchy coating that results.
Carefully add the chicken to the pan—don't crowd the pan, or the chicken won't brown fully. Cook for 2-3 minutes per side until the batter is golden brown, then transfer to the prepared baking sheet.
Repeat with the remaining chicken until all pieces are flash-fried, adding the remaining 1/2 cup canola oil to the pan as necessary.
Bake the chicken for 15 minutes until fully cooked.
Assemble the sandwiches:
Open 8 potato buns and generously spread buttermilk herb mayonnaise on each bottom bun. Top the mayonnaise with 3-4 pickle rounds and a handful of shredded lettuce. Complete the sandwich with the chicken and the top bun, and serve immediately.