Line a large baking sheet with parchment paper. (Don’t use wax paper because it will melt.)
In a 3½-quart enamel-coated cast-iron Dutch oven, bring brown sugar, cream, and baking soda to a full boil over medium heat. Cook, stirring occasionally, with a wooden spoon, until a candy thermometer registers 240°.
Remove from heat; quickly stir in pecans, butter, and vanilla, stirring just until mixture thickens. Using a metal spoon, quickly drop mixture by tablespoonfuls 2 inches apart onto prepared pan. Garnish with salt, if desired. Let stand until firm, about 45 minutes.
Recipe by Taste of the South at https://tasteofthesouthmagazine.com/pecan-pralines/