Use to make pastry chef Sarabeth Levine's Whipped Cream.
Cut 1/8-inch off the bottom end of each vanilla bean. Stand beans, cut ends down, in a large glass jar at least 12 inches tall; add 2 inches of rum. Cover jar and let stand until beans are softened, at least 2 weeks.
To use, hold cut end of bean over the bowl of the mixture you wish to flavor. Starting at the uncut end, squeeze down the length of the bean to extrude pulp. If using the bean, split lengthwise to release more flavor. If a recipe calls for less than a whole bean, return unused part to jar, cut side down. Beans can be kept in rum at room temperature up to 6 months.