How to Make It
Preheat oven to 300°.
Combine first 4 ingredients in a medium, heavy saucepan. Heat mixture over medium heat to 180° or until tiny bubbles form around edge (do not boil), stirring occasionally. Remove from heat.
Combine 1 teaspoon sugar, salt, and egg yolks in a medium bowl, stirring well with a whisk. Gradually add hot milk mixture to egg mixture, stirring constantly with a whisk. Stir in rum.
Divide milk mixture evenly among 6 (4-ounce) ramekins or custard cups. Place ramekins in a 13 x 9-inch baking pan; add hot water to pan to a depth of 1 inch. Bake at 300° for 50 minutes or until center barely moves when ramekin is touched. Remove ramekins from pan; cool completely on a wire rack. Cover and chill 4 hours or overnight.
Sift 1 1/2 teaspoons sugar evenly over each custard. Holding a kitchen blow torch about 2 inches from the top of each custard, heat the sugar, moving the torch back and forth, until sugar is completely melted and caramelized (about 1 minute). Serve immediately or within 1 hour.