01 -
Line an 8x8-inch pan with parchment paper, leaving overhang on two sides. Lightly butter the parchment.
02 -
Add the white chocolate chips, butterscotch chips, marshmallow creme, rum or rum extract, vanilla, cinnamon, and nutmeg to a large heatproof bowl. Set it close to the stove.
03 -
In a heavy saucepan, combine sugar, heavy cream, butter, and salt. Cook over medium heat, stirring until the butter melts and the mixture reaches a full boil.
04 -
Continue boiling, stirring often, until the mixture reaches 235-240°F on a candy thermometer, about 4-6 minutes once boiling.
05 -
Immediately pour the hot mixture over the chocolate mixture. Beat with a hand mixer on low or stir firmly with a sturdy spoon until smooth, glossy, and thick.
06 -
Fold in 1/2 cup of the pecans. Spread into the prepared pan, sprinkle with the remaining pecans, and press lightly. Refrigerate until firm, about 2 hours.
07 -
Lift the chilled fudge from the pan. Cut into 36 small squares with a warm, dry knife.