►Pat chicken breast dry and season with salt and pepper. To butterfly: slice each breast down the middle lengthwise, without separating halves. Fill each breast with ¼ cup cheese blend. *Note: if using smaller chicken breasts, use less cheese. Don’t use more than ¼ cup for each.
►Preheat oven to 375°F. Heat a drizzle of olive oil in a large oven-proof pan. Sear the top side of each breast for 3 to 5 minutes. Flip the chicken and finish cooking in the oven for 10 to 12 minutes.
►On a baking sheet, combine bread cubes with a drizzle of olive oil, salt, and pepper and bake 10 to 12 minutes until toasted.
►Meanwhile, whisk together garlic, lemon juice, whole grain mustard, mayonnaise, parsley, a pinch of salt and pepper, and ¼ cup cheese blend. Set aside to use as dressing.
►Once chicken is cooked through, turn oven to broil setting. Sprinkle cheese blend on top of each breast. Broil for 2 to 3 minutes until golden brown.
►Toss greens with tomatoes, croutons, and dressing. Plate chicken breast on top and garnish with any leftover cheese, if desired.