Prepare the Pan: Line a 9×13-inch baking pan with parchment paper and lightly butter it. This makes it easy to lift the fudge out later and ensures a clean release when slicing.
Combine Sugar and Pecans: Sift the powdered sugar through a fine-mesh sieve into a large mixing bowl to remove any lumps. Add the cooled, crushed pecans and whisk them together. Blending them first helps the sugar absorb the pecan oils, creating a smooth texture that makes this fudge extra special.
Cook the Butter Mixture: In a large, heavy-bottomed saucepan over medium heat, combine the butter, granulated sugar, dark brown sugar, heavy cream, and sea salt. Stir constantly with a heatproof rubber spatula or wooden spoon until the mixture comes to a steady boil.
Boil for Four Minutes: Once the mixture begins boiling, set a timer for 4 minutes and continue stirring constantly. Keep the heat steady — not too high — to prevent scorching. This precise timing ensures the fudge sets properly without becoming grainy.
Combine and Mix: Remove the saucepan from the heat and immediately pour the hot butter mixture over the powdered sugar and pecans. Add the vanilla extract and stir vigorously, folding the mixture until smooth. If you encounter any stubborn lumps, press and “slap” the mixture against the bowl with your spatula to break them up and create a velvety consistency.
Pour and Cool: Transfer the fudge into the prepared pan, spreading it evenly with a spatula. Tap the pan gently on the counter to remove air bubbles. Let it cool at room temperature for about 3 hours, or until fully set and firm.
Slice and Serve: Once cooled, lift the fudge out of the pan using the parchment paper and cut into small squares. Each piece should be smooth, rich, and filled with buttery pecan goodness.
