Choose your rum: use 37% alcohol by volume for standard strength, or 60% for a stronger liqueur. Also choose your vanilla level: use both sachets of flavor for the full vanilla taste, or just 1 sachet if you prefer less vanilla.
Mix caramelized condensed milk, vanilla sugar, the flavor sachets, and rum using a mixer for 2 minutes.
Let the liqueur steep for 1 to 2 days at room temperature to round off the taste, or drink it immediately if you prefer. This recipe yields approximately 1200 ml.