Add Angostura bitters, butter, sugar, and cinnamon in a small sauce pot over medium heat; simmer and stir for 3-5 minutes, until the sugar is completely dissolved.
Remove the mixture from heat and add creamer.
Place the popped popcorn in a large mixing bowl and evenly pour heated mixture over popcorn.
Distribute popcorn on a large baking sheet and put it in the oven for 8-10 minutes; stir every 2-3 minutes.
Allow the popcorn to cool at room temperature and serve.