Line two baking sheets with parchment paper or non-stick silicone baking mats; set aside.
Stir together the sugars and baking soda in a 3-quart saucepan. Stir in the half & half and place over medium heat. Cook, whisking occasionally, until the mixture reaches 235 degrees F on a candy thermometer.
As soon as the mixture reaches 235 degrees, whisk in the butter until it is completely melted, about 1 to 2 minutes.
Remove the mixture from the heat and stir in the pecans and bourbon until the nuts are evenly coated. Switch to a wooden spoon and stir vigorously until the mixture thickens, about 3 to 5 minutes.
Working quickly, drop tablespoons of the mixture onto the prepared baking sheets. Let sit at room temperature until completely dry, about 20 minutes. Store in an airtight container at room temperature for up to 1 week.