In medium saucepan bring water to boiling. Stir in sugar, corn syrup, and butter. Cook and stir over medium-high heat until mixture boils, stirring to dissolve sugar (about 7 minutes). Clip candy thermometer to side of pan. Reduce heat; continue boiling at moderate, steady rate, stirring occasionally until thermometer registers 300 degree F, hard-crack stage (45 to 50 minutes).
Remove from heat; stir in flavoring and gel food coloring. Let stand until thermometer registers 220 degree F (about 20 minutes). Butter 2 baking sheets. Place sticks 4 inches apart on sheets.
Working quickly, spoon 1 tablespoon of candy mixture over top 1 inch of each lollipop stick (do not spread; mixture will flow out). Cool completely. Wrap each lollipop in plastic wrap. Store at room temperature up to 2 weeks. Makes 18 to 20 lollipops.