Combine brown sugar, white sugar, water, and corn syrup in a medium saucepan. Bring to a boil, stirring occasionally.
Lower the heat to a simmer and simmer for 10 minutes until thickened slightly.
Remove from the heat. Stir in salt, vanilla extract, and maple flavoring. Allow to cool for 15 minutes before using.
Once completely cool, pour into jars and refrigerate.
