Prepare Your Baking Dish: Line an 8-inch square baking dish with parchment paper, allowing some hanging over the sides for easy removal later.
Melt the Chocolate: In a double boiler over simmering water, melt the chocolate chips slowly. Stir frequently until smooth. Alternatively, use a microwave in 30-second bursts, stirring in between.
Add Sweetened Condensed Milk: Once melted, remove the chocolate from heat and stir in the sweetened condensed milk until thoroughly combined.
Incorporate Pumpkin: Gently fold in the pumpkin puree, vanilla extract, and pumpkin spice. Ensure no lumps remain and everything is evenly mixed.
Pour into Dish: Transfer the fudge mixture into the prepared baking dish and smooth the top with a spatula.
Chill: Refrigerate for at least 2 hours, or until fully set. You can also place it in the freezer for quicker setting.
Cut and Serve: Once set, lift the fudge out using the parchment paper, cut into squares and enjoy! Store any leftovers in an airtight container in the fridge.