In a medium-size heavy saucepan, combine carrots, pears, pineapple, lemon juice, and cinnamon.

Bring to a boil over medium heat.

Simmer for 20 minutes, stirring often.

Remove from heat.

Sprinkle pectin over mixture and stir until dissolved.

Bring mixture to a boil, stirring constantly.

Add sugar.

Bring to a full boil and boil hard for 1 minute.

Remove from heat and stir in vanilla.

Ladle into clean jars and process for 10 minutes in boiling-water bath.