Start off by prepping your chicken breast by trimming them and then placing them on some plastic wrap, adding plastic wrap on top of them, and then flatten them out until they are a 1/4” thick. Or more evenly in their thickness.
Create your marinade. In a mixing bowl add all of your ingredients, they are as follows: avocado oil, basil, lemon, garlic, red pepper flakes, black pepper, kosher salt, cumin, oregano and thyme. Whisk together and make sure you do this beforehand so the flavors can marry, I recommend one hour prior.
In a large bowl or zip lock bag, add your chicken breast and pour in your marinade. Mix well and zip lock airtight and place in the fridge. The longer you marinade the better, a minimum of 4 hours and up to 24 hours.
One hour before you begin your cooking, get a cast iron over medium low heat and add in the avocado oil and butter. Melt and mix for a few mins, now toss in your red onions and mushrooms, salt and mix. Let them cook down for about 15 mins and then add 1-2 cups of red wine. Don’t let them sit for long and every few mins make sure to stir. Reduce the red wine and then add another cup until your onions and mushrooms are caramelized.
Thirty mins in make sure to get your chicken out and pat dry with a pepper towel. Fire up your grill for direct grilling. You are looking for a 400-450 degree cooking surface.
Grill your chicken for 4 mins and turn for an additional 2 mins, flip and grill for 3 mins and check the internal temp. Remove the chicken at 160 degrees internal and rest on a wire rack.
Toast your Ciabatta bread.
Slice your chicken in 1/4’ strips and build your sandwich in this order: Arugula, the chicken, gruyere cheese (torch or broil) and then top with the red wine onions and mushrooms.
Serve and enjoy with family and friends!