Prepare the Mixture. In a saucepan over medium heat, whisk together cocoa powder, granulated sugar, and salt. Gradually whisk in the whole milk until smooth and combined. Cook the mixture, stirring constantly, until it thickens slightly, about 5 minutes. Remove from heat and stir in the vanilla extract. Let the mixture cool to room temperature.
Fill the Molds. Pour the cooled chocolate mixture into popsicle molds, leaving a little space at the top for expansion. Insert popsicle sticks into the molds. If desired, sprinkle your choice of toppings onto the fudgesicles.
Freeze. Place the filled molds in the freezer and let them freeze until solid, about 4-6 hours or overnight.
Enjoy. Once the fudgesicles are completely frozen, remove them from the molds by running them under warm water for a few seconds. Serve immediately and enjoy!