- Coat an 8-inch square baking dish with nonstick cooking spray.
- In a large saucepan, bring the butter, heavy cream, granulated sugar, brown sugar, and salt to a boil over medium heat, stirring frequently.
- Allow to boil for 5 minutes, stirring constantly, then remove the pan from the heat.
- Stir in the pecans and vanilla.
- Add the confections' sugar and stir until smooth and well combined.
- Spread the mixture into the baking dish.
- Allow to cool to room temperature then cut into 1-inch squares and serve, or store in an airtight container until ready to serve.