Place bourbon in a clean jar, and add cool brown butter. Let sit at room temperature for 1 hour, then transfer to the refrigerator, and let infuse for 1 day. Pour infused bourbon through a damp paper towel-lined strainer into a clean jar. You could also use a coffee filter, but a damp paper towel is a cheap, easy solution. Store bourbon in the refrigerator for a few weeks or in the freezer for several months.