Before adding chicken to the slow cooker, pat it completely dry with paper towels and sear it briefly in a hot skillet. This creates a flavorful crust and prevents the meat from steaming, ensuring juicier results.

Mix your Dijon mustard, red pepper flakes, and garlic together before adding to the slow cooker. This creates a flavor paste that distributes evenly and intensifies the spice profile throughout the dish.

Reserve half your lemon zest and stir it in during the last 15 minutes of cooking to preserve its bright, fresh citrus notes that the long cooking process would otherwise diminish.

Mix cornstarch with a splash of cold water to create a slurry before adding it to thicken the sauce, whisking constantly to prevent lumps and achieve a glossy, restaurant-quality consistency.

Add the fresh parsley as a garnish just before serving rather than during cooking—this preserves its vibrant color and herbaceous flavor that complements the tangy lemonade sauce perfectly.