Flatten out the chicken breast and season on both sides with salt + pepper and Italian seasoning.
In a cast iron skillet, melt the butter and add olive oil. Cook the chicken breast for 3-4 mins on each side. Once it’s cooked, set aside, and let the chicken rest.
Toast the two pieces of bread and spread the pesto on both sides. Add the arugula/spring mix along with the sliced tomatoes and onions.
Cut the chicken into small strips or you can leave it whole, and place it on top of the mixed greens, close the sandwich, and cut it in half.
