01 -
Place blueberries, brown sugar, honey, lemon zest, lemon juice, cinnamon, and nutmeg in the slow cooker and mix thoroughly.
02 -
Cover the slow cooker with the lid and cook on high for 1 hour.
03 -
Transfer the blueberry mixture to a blender and process until a smooth consistency is achieved.
04 -
Return the blended mixture to the slow cooker. Prop the lid open with a wooden spoon to allow steam to escape, aiding reduction.
05 -
Cook on low for an additional 4 to 5 hours until thickened, stirring occasionally to prevent sticking.
06 -
Ladle the finished blueberry butter into sterilized 240 ml mason jars. Seal and refrigerate for up to 2 months.