In a large pot, combine apples, brown sugar, cider, cinnamon, and lemon juice.
Bring to a boil over medium-high heat, then reduce to a simmer. Cook uncovered for 30 minutes, stirring often, until apples are very soft.
Purée with an immersion blender until smooth.
Continue cooking 10-15 minutes, stirring constantly, until thickened (it should mound on a spoon).
Remove from heat and stir in vanilla. Let cool before jarring.