Puree the apple and rhubarb in a food processor or blender until smooth.
Pour the mixture into a pot and stir in the honey, vanilla extract, and cinnamon.
Bring the mixture to a boil, stirring occasionally.
Reduce the heat to a simmer and continue stirring every few minutes.
Let it cook for about 15–20 minutes, or until the mixture thickens to your desired consistency.
Pour into a clean jar and let it cool completely (follow canning instructions if preserving).
Store in the refrigerator and enjoy as a spread or topping.
