MAKE THE CHOCOLATE GANACHE BALLS. Place the chocolate in a medium-sized, heat-resistant bowl.
Meanwhile, in a small saucepan, whisk the cream, sugar, cocoa powder and salt until well combined.
Bring the mixture to a gentle simmer over medium heat.
Pour the hot cream mixture over the chocolate, gently wiggle the bowl so that all the chocolate is submerged, and then let it sit for 2 minutes before whisking until a homogeneous, silky ganache forms.
Refrigerate the ganache until set, at least 2 hours.
Using a medium-sized (1-ounce) cookie scoop, scoop the ganache into mounds.
Place the scooped mounds onto a parchment-lined baking sheet and freeze until solid.
Place the frozen mounds into a zip-top bag and store in the freezer until ready to use for up to 3 months.
MAKE THE HOT CHOCOLATE. In a small saucepan, heat the milk and cream over medium heat until it begins to steam.
Add the Chocolate Ganache Balls and stir to melt.
Continue to heat until desired temperature. Pour into a mug and top with whipped cream and your favorite toppings.