3 ounces dark chocolate (70% or higher), chopped
1 tablespoon dark cocoa powder
1/4 cup sweetened condensed milk
3/4 cup whole milk
Place the dark chocolate and cocoa powder in a heat safe bowl or liquid measuring cup. Bring the sweetened condensed milk and milk to a gentle simmer over medium heat. Pour the hot milk mixture over the dark chocolate and let sit for 15 seconds. Whisk the mixture until the chocolate is fully melted and the cocoa is smooth (if you whisk vigorously, the mixture will get frothy—if you mix slowly, it will stay smoother). Season with salt and cayenne, if using. Pour into a mug and drink warm.