Slice the chicken breasts in half horizontally to create 4 equal size pieces.

In a medium shallow bowl, combine the flour, garlic powder, ½ teaspoon salt, and ¼ teaspoon black pepper. Set aside.

In a separate medium bowl, whisk the eggs and set aside.

In a third medium shallow bowl, combine the panko and Parmesan cheese.

Dredge the chicken in the flour mixture, dip into the eggs, and finally coat with the panko mixture.

Heat oil in a large cast iron skillet over medium high heat. Cook the chicken in the hot oil for 2 to 3 minutes on each side, until cooked through. Remove to a paper towel lined plate.

In a small bowl or jar, whisk together the Greek yogurt, lemon juice, mustard, honey, garlic, salt, and pepper until smooth to make the lemon dressing. Set aside.

Preheat the broiler. Cut the croissants in half lengthwise and place them on a baking sheet. Brush with melted butter and sprinkle with ¼ cup of Parmesan cheese. Broil until slightly toasted and cheese is melted, about 1 to 2 minutes.

In a medium bowl, combine the lettuce, remaining Parmesan cheese, and dressing. Toss until well coated.

To assemble the sandwiches, place chicken on the bottom halves of the croissants, drizzle with hot honey, if using. Top with avocado slices and the lettuce mixture, then cover with the croissant halves. Serve immediately.