Line an 8-inch square baking pan with foil or parchment paper, extending the parchment paper over the edges of pan. Lightly grease with butter or non-stick spray.
In a double boiler or a heatproof bowl set over simmering water, melt the chocolate. Stir gently and consistently to avoid burning the chocolate. (Or use a medium saucepan over low heat, stirring frequently just until smooth) Tip: If the chocolate seizes while melting, add 1 tsp hot water, whisking until smooth.
Add the sweetened condensed milk. Stir continuously until well combined.
Add the vanilla extract, Gingerbread spice, and salt. Stir well to ensure these ingredients are evenly distributed.
Pour the mixture into the prepared pan. Use a spatula to spread it evenly, ensuring a consistent thickness. Add sprinkles to your liking.
Place the pan in the refrigerator to allow the fudge to cool and set. This process usually takes at least an hour. For optimal results, let it chill overnight.
Once the fudge has set, lift it out of the pan using the parchment paper overhang. Place it on a cutting board and, with a sharp knife, cut it into neat squares. Serve and enjoy!