The blueberry mixture can be prepared and refrigerated at least 40 minutes and up to 3 days in advance. Store lightly covered at room temperature for up to 3 days, or freeze for up to 2 months.

Perfect for sharing at family gatherings, picnics, or an afternoon treat, these bars combine the buttery goodness of a shortbread crust with a juicy, jam-like blueberry filling and a crumbly oat ...