Combine the apples, cinnamon, ginger, nutmeg, brown sugar, maple syrup and sugar in a slow cooker. Cook on high for 3 hours or low for 5 hours.
Turn off the slow cooker and add the fresh lemon zest to the mixture. Using an immersion blender, puree until smooth. (If you don't have an immersion blender, transfer the mixture to a blender and puree until smooth).