• Stir the water and brown sugar together in a heavy-bottomed 2 to 2 1/2 quart saucepan with high sides. Place the pan over medium high heat and stir until the sugar is melted and the mixture comes to a boil. Lower the heat to medium and allow it to boil for 4 minutes. When the time is up, gently drop one pat of butter into the mixture and stir until the butter is melted completely. Repeat the process with one pat of butter at a time, until all the butter has been melted and incorporated. Remove the pan from the heat. If using the extract, add it and stir it in now. Take care, as it will bubble up enthusiastically.
• Let the syrup stand in the pan for five minutes before pouring into a heat-proof pitcher (for immediate use) or into a clean canning jar (for longer storage.) Serve warm to hot. Store leftover syrup in a tightly closed canning jar in the refrigerator for up to a month.

To Reheat Leftover Syrup:

• Remove the lid from the jar and microwave in 15 second bursts, stirring after each burst, OR place the jar, still lidded, on a folded dishcloth in a saucepan with simmering water, using an oven mitt or canning tongs to lift and swirl the jar from time to time until it flows freely and is warm through.