Preheat the oven to 400 degrees F. Spray a wire cooling rack with cooking spray and set it on top of a large baking sheet.
Place the breadcrumbs in a shallow bowl.
Using a sharp knife, cut into the long-side of the chicken breast, opening it like a book, and taking care not to cut all the way through the breast. Repeat with the second piece of chicken.
Spread the pesto among the insides of the breasts, then evenly distribute the ham and cheese on one side of each. Fold over to seal.
Dredge each filled chicken breast in the breadcrumbs, carefully turning to coat both sides.
Place them on the prepared wire rack, spray the tops well with cooking spray, and bake for 20 to 25 minutes, until the chicken is cooked through.