Line an 8" x 8" baking dish with foil, leaving an overhang on the sides, and spray with non-stick spray. Set aside.
In a medium size saucepan, combine the sugar, evaporated milk, pumpkin purée, butter, salt, and spice. Heat over medium heat and bring to a boil. Allow to boil for at least 8 minutes and up to 12 minutes, stirring often, and stopping when mixture pulls away from sides and bottom of saucepan as you stir. Remove from heat.
1 and ½ cups (300g) granulated sugar, 1-5 ounce can (147mL) evaporated milk, ½ cup pumpkin purée1, 2 Tablespoons (28g) unsalted butter, 1 teaspoon salt, 1 Tablespoon pumpkin pie spice
Add the white chocolate chips and mini marshmallows to the saucepan and stir vigorously until completely melted. Stir in pecans (if using). Pour mixture into prepared pan, sprinkle with more chopped pecans (if desired), and allow to chill in refrigerator for at least 30 minutes.
12 ounces (340g) white chocolate chips, 2 cups (90g) mini marshmallows, ¼ cup (30g) finely chopped pecans
When fudge is completely set, lift from pan using foil overhangs and cut into desired size squares. Fudge can be stored in an airtight container at room temperature up to 1 week or in the refrigerator up to 2 weeks. Fudge freezes well, up to 3 months.
Notes
Pumpkin: I always measure pumpkin purée with measuring cups as the moisture content can wildly change the weight measurements, depending on the brand.
All nutritional values are approximate and provided to the reader as a courtesy. Changing ingredients and/or quantities will alter the estimated nutritional calculations.