Gather all your ingredients and measure them out. This step is crucial for a smooth cooking process.
In a medium saucepan, combine the granulated sugar, brown sugar, and light corn syrup. Stir until well combined.
Place the saucepan over medium heat. Stir continuously until the sugars dissolve completely and begin to bubble, about 5 minutes.
Once bubbling, add the butter and heavy cream. Stir continuously until the butter is melted and everything is well combined.
Remove from heat and carefully stir in the baking soda and vanilla extract. The mixture may bubble up, so be cautious.
Allow the caramel syrup to cool in the saucepan for about 10 minutes. It will thicken as it cools.
Pour the cooled syrup into a storage jar or bottle, leaving some space at the top for expansion when reheated.
