Step 1: Mix the Base

1. Combine Dry Ingredients: In a small bowl, whisk together cocoa powder, sugar, and cornstarch.
2. Heat Milk and Cream: In a saucepan, heat milk and cream over medium heat until warm but not boiling.

Step 2: Blend in the Chocolate

1. Add Dry Ingredients: Gradually whisk the cocoa mixture into the warm milk to prevent lumps.
2. Stir in Chocolate: Add chopped chocolate and stir until melted and smooth.

Step 3: Thicken the Mixture

1. Simmer and Stir: Continue heating while stirring constantly until the mixture thickens, about 5 minutes.
2. Check Consistency: It should coat the back of a spoon like custard.

Step 4: Serve and Garnish

1. Pour into Cups: Divide the hot chocolate between two cups.
2. Add Toppings: Top with whipped cream, chocolate shavings, or your favorite garnish.