Cut the vanilla pod lengthways and scrape out the pulp. Drain the cherries in a sieve, discarding the drained liquid.
In a saucepan, combine the drained cherries and sugar over medium-high heat. Stir frequently until the sugar completely dissolves and the mixture comes to a boil. Boil for 5 minutes.
Add the amaretto, lemon juice, vanilla pod, and scraped vanilla pulp to the saucepan. Reduce heat to medium and simmer for 15-20 minutes.
Remove the vanilla pod pieces from the saucepan. While the mixture is still hot, carefully pour it into jam jars. Immediately invert the jars (turn them upside down) and allow them to cool completely.