Store any leftovers sealed in an airtight container in the refrigerator for up to 3 days. If using whole chicken breasts, cook for 12-16 minutes to ensure they remain tender and juicy. Avoid exceeding 2 hours of marinating to prevent the chicken from becoming too tangy. For best results, check the internal temperature before flipping to avoid overcooking. If the mustard sauce is not sticking, dredge the chicken thoroughly and let it sit before cooking. If the lemon makes the chicken too tangy, reduce lemon juice for a milder flavor.