For a more Italian flavor, omit the lemon pepper and use fresh basil leaves instead of the mint. This pesto is also a tasty accompaniment to lamb or pork.
Place a chicken breast half on the cutting board skin-side up. With a small knife or boning knife, make a pocket 2 inches deep and about 3 inches long in the breastbone side of the meat.
Combine all ingredients for pesto filling in a blender or food processor. Hold open the pocket of one breast half and spoon in one fourth of the pesto mixture. Repeat with remaining breast halves and filling.