01 - Line two baking sheets with parchment paper or silicone mats to prevent sticking.
02 - In a heavy-bottomed saucepan over medium heat, combine granulated sugar, brown sugar, butter, heavy cream, milk, and salt. Stir constantly until the butter melts and the sugars dissolve completely.
03 - Attach a candy thermometer to the pan. Continue cooking, stirring occasionally, until the mixture reaches 236°F (soft ball stage), about 8–10 minutes.
04 - Remove from heat immediately. Stir in vanilla extract and toasted pecans. Beat briskly with a wooden spoon for 2–3 minutes until the mixture thickens, becomes creamy, and loses its gloss while remaining pourable.
05 - Working quickly, drop heaping tablespoons of the mixture onto the prepared baking sheets, spacing them 2 inches apart to allow for spreading.
06 - Let pralines cool at room temperature for at least 20 minutes until completely set and firm to the touch.