How to Make It
Combine the dark brown sugar, granulated sugar, heavy cream and butter in a medium saucepan; stir to combine. Heat over medium-high; bring sugar mixture to a boil, stirring frequently. Cook until the mixture reaches 235°F (soft ball stage) on a candy thermometer; remove from heat and whisk continuously for about 3 minutes.
Add the vanilla extract and pistachios, stirring until mixture has slightly thickened, about 1 minute.
Spoon about 2 tablespoons of the mixture per praline onto a rimmed baking sheet lined with parchment paper. Sprinkle evenly with sea salt and finely chopped pistachios, if desired. Cool for 30 minutes. Enjoy immediately or store in an air-tight container for up to 5 days.