This recipe appears in:BraveTart: Homemade Swiss Miss with Mini Marshmallows
Look, this isn't fancy drinking chocolate, liquid chocolate, or even hot chocolate. This is cocoa. Hot cocoa. It's light enough and not too sweet, making it highly drinkable even with a rich holiday breakfast. Best enjoyed with one to five hundred mini marshmallows, crispy or otherwise.
Even if you hate white chocolate, don't leave it out. It doesn't impart its signature flavor, but rather contributes to the body and sweetness of the recipe. Likewise, the small amount of coffee powder doesn't make this mocha, but rounds out the chocolate flavor in a subtle but important way. For both the white and dark chocolate, use bars of chocolate rather than chips. Chips contain various additives to help retain their shape while baking and make for a weakly flavored, poorly textured cocoa.
This cocoa mix keeps for months, stored in a jar. Make a double batch for gift giving or just to get you through the winter.
Note: All measurements are in weights, as volume measures can be very imprecise. I strongly recommend using a scale for all pastry projects. Serious Eats' recommended kitchen scale is the Oxo Good Grips Scale with Pull Out Display.
Make the cocoa mix:
In the bowl of a food processor, combine the powdered sugar, white chocolate, cocoa powder, dark chocolate, salt, vanilla bean seeds and instant coffee. Pulse until the mixture is finely ground. If the processor starts to get warm, take a break for a minute to let it cool. Continue pulsing until no large bits of chocolate remain. (Don't run the processor continuously, as this will cause the machine to warm and will start to melt the chocolate a bit, creating a weird clumpy mixture.)
Transfer the ground cocoa mix to an airtight container. The mixture will store indefinitely at room temperature.
To prepare the cocoa:
Whisk 3 tablespoons (about one ounce) of cocoa mix into 6 ounces of boiling milk. Adjust with more cocoa to taste. Add marshmallows.
If you're serving a crowd and want to prepare all of the cocoa at once, start by bringing a half gallon of milk (along with the reserved vanilla pod, if you like) to a boil in a pot over medium high heat. Turn the heat to medium and whisk in all of the cocoa, a half cup at a time. Whisk continuously until all of the mixture has dissolved.
Serve immediately, or transfer to a thermos.