Step 1: In a medium saucepan, whisk together the unsweetened cocoa powder, granulated sugar, and a pinch of salt. Whisking them dry first helps prevent clumps when liquids are added.
Step 2: Gradually pour in about 1/2 cup of the whole milk, whisking continuously to form a smooth paste. This paste is key to preventing lumps in your final Homemade Hot Chocolate. Continue whisking until it’s completely smooth.
Step 3: Slowly add the remaining whole milk and the heavy cream to the saucepan, continuing to whisk until everything is well combined. Turn the heat to medium-low.
Step 4: Add the chopped dark chocolate to the milk mixture. Stir constantly with a whisk or a rubber spatula as the mixture heats up. Keep stirring until the chocolate is fully melted and smoothly incorporated, and the Homemade Hot Chocolate is steaming gently. Do not allow it to boil, as this can scorch the milk and dull the chocolate's flavor.
Step 5: Once the chocolate is melted and the mixture is hot, remove the saucepan from the heat. Stir in the vanilla extract. Give it a final taste and adjust sweetness if desired.
Step 6: Ladle the rich, creamy Homemade Hot Chocolate into your favorite mugs. Serve immediately, topped with your choice of garnishes.