In a 4 quart or larger saucepan or Dutch oven, mix together the brown sugar, heavy cream, butter, corn syrup, and salt.
Heat the sugar mixture over medium heat until boiling, stirring constantly. Clip on the candy thermometer and let the mixture boil over medium heat until it reaches a temperature of 240℉, stirring frequently.
When the temperature reaches 240℉, remove from the heat and let cool to 150℉. (about 20 minutes) Meanwhile, prepare a baking sheet with waxed paper or parchment paper sprayed with nonstick cooking spray. Spray 2 tablespoons with nonstick cooking spray.
Once the praline mixture has come to temperature, stir in the toasted pecans and vanilla extract, and continue stirring for 3-4 minutes or until some of the glossiness is gone.
Working quickly, using the sprayed spoons, spoon the candy mixture onto the prepared baking sheet.
Let the candies set completely before serving.
Notes
Toasted walnuts can be used in place of the pecans.
To store the pecan pralines, let them cool fully, then wrap each candy individually in plastic wrap, and store it in an airtight container at room temperature for up to 3 weeks.
When spooning the candy onto the baking sheet, you will want to work quickly as they start to set up. You may want to enlist the help of a family member or friend.