In a medium saucepan, combine milk, butter, and vanilla bean. Heat over medium heat until butter is melted and mixture is hot, but not boiling. Remove from heat and let cool until lukewarm.

In a large bowl, whisk together flour, sugar, eggs, egg yolks, rum, and salt until smooth. Gradually whisk in the lukewarm milk mixture until smooth.

Cover the bowl with plastic wrap and refrigerate for at least 24 hours.

Preheat oven to 375°F. Grease canelé molds with beeswax or cooking spray. Fill each mold 3/4 of the way full with batter.

Bake canelés for 15 minutes. Reduce oven temperature to 350°F and continue baking for 50-55 minutes, or until the canelés are deeply browned and crispy on the outside. Let cool in the molds for a few minutes before unmolding and serving. Enjoy!