Balsamic reductions are wonderful syrups for drizzling under or over desserts such as brownies, cheesecake, custards, and especially ice cream.  Also nice over pancakes and waffles!  Experiment with flavors from blueberry and strawberry to chocolate and espresso. Method 1: Using a stainless steel sauce pan, bring desired amount to gentle simmer for 3-5 minutes.  Syrup will thicken as it cools so watch carefully so as not to over simmer. Method 2: Pour shallow amount in large glass or ceramic dish and leave at room temperature until desired viscosity.  Natural evaporation makes a natural reduction.