01 - Line a 9x9-inch baking pan with parchment paper, leaving a generous overhang for effortless removal.
02 - In a medium saucepan over medium heat, combine granulated and brown sugars, unsalted butter, evaporated milk, pumpkin puree, instant espresso powder, cinnamon, nutmeg, and salt. Stir continuously until the mixture comes to a boil.
03 - Maintain a gentle boil, stirring for 8 to 10 minutes, until the temperature reaches 234°F on a candy thermometer.
04 - Remove saucepan from heat. Immediately add white chocolate chips and marshmallow crème, stirring vigorously until smooth and homogeneous.
05 - Incorporate vanilla extract, then transfer the mixture to the lined pan, smoothing the top evenly.
06 - In a small skillet over medium heat, melt unsalted butter. Add pecan halves, granulated sugar, and a pinch of salt. Cook, stirring often, until sugar dissolves and pecans are thoroughly coated and toasted, approximately 3 to 4 minutes.
07 - Immediately scatter praline over surface of fudge and gently press to adhere.
08 - Allow fudge to cool at room temperature for 30 minutes, then refrigerate for at least 1 hour until fully set.
09 - Lift fudge from pan using parchment overhang. Slice into squares and serve as desired.