This recipe is excellent exactly as written, but there are several easy variations worth knowing about for when you want to change things up or adapt it to what you have on hand. If you prefer dark meat, boneless skinless chicken thighs are a wonderful substitute for the breasts — they are even more forgiving in the slow cooker, stay exceptionally moist throughout the long cooking time, and have a slightly richer flavor that pairs beautifully with the sweet and tangy sauce. Be aware that thighs tend to release a bit more liquid during cooking, which can make the finished sauce slightly looser than when using breasts, but the flavor will be equally outstanding.
For a lighter version of the sauce, you can substitute half-and-half or whole milk for the heavy cream. The sauce will be slightly less rich and a little thinner, but still very good. If you enjoy a touch of heat alongside the sweetness, add a generous pinch of crushed red pepper flakes or a teaspoon of prepared horseradish to the honey mustard mixture before pouring it over the chicken. Either addition gives the dish a pleasant warmth that cuts through the richness of the sauce in a very appealing way.
To turn this into a more substantial one-pot meal, stir in a bag of cooked egg noodles or a generous quantity of steamed broccoli florets directly into the slow cooker at the very end of the cooking time, tossing everything together so the noodles or broccoli are thoroughly coated in the honey mustard sauce. This approach essentially doubles the volume of the dish and makes it feel even more complete as a standalone dinner without requiring any additional sides.
Leftovers from this recipe store exceptionally well. Transfer any remaining chicken and sauce to an airtight container and refrigerate for up to four days. When reheating, do so gently over low heat on the stovetop or in the microwave at a reduced power setting. The sauce tends to thicken considerably when chilled — if it seems too thick when you reheat it, simply stir in a splash of cream, milk, or even a little water to bring it back to its original silky, pourable consistency. The flavor actually deepens and improves overnight, making this one of those rare dishes that is arguably even better as a leftover than it is on the day it is made.
