Chop the apples and plums into 1-inch pieces, discarding the pits and cores. Place the fruit, maple syrup, water, and cinnamon sticks in a medium sized saucepan.
Cover the pot and simmer over medium-low heat for 20 minutes, stirring occasionally. Remove the lid and simmer for an additional 20 minutes, stirring occasionally. If necessary, add a couple more tablespoons of water during the cook time.
For a chunkier applesauce, mash with a potato masher or wooden spoon. If you'd like it smoother, puree it in a blender or food processor.
I like to leave some skin on the apples for texture. I peel about half of it off and leave the other half on.