Transforming these Christmas Cookie Bars into a gluten-free delight is surprisingly simple and equally delicious! The key swap here is the all-purpose flour. Replace it with an equal amount of a high-quality gluten-free flour blend – one that's designed to be a direct substitute for traditional flour. Look for a blend that includes xanthan gum, which mimics gluten's binding properties, ensuring your cookie bars hold together beautifully. Also, double-check that your M&Ms and sprinkles are labeled gluten-free, as some brands may contain gluten or be processed in facilities with gluten-containing products.