The first thing necessary for good hot chocolate is good milk. Those lucky enough to live in the San Francisco and Sacramento areas can get my favorite, organic Straus milk, at higher-end grocery stores. Partially, this milk is good because it’s just very good organic milk. I think the fact that it is not homogenized also makes a difference. According to Harold McGee in On Food and Cooking, “Homogenized milk is whiter, blander, less stable to heat, and more sensitive to spoilage by light than unhomogenized milk.” Homogenization is what blends the milk and keeps the fat from floating to the top (not to be confused with pasteurization which kills bacteria).
Therefore, you’ll get floating blobs of milkfat (which are so good) that you have to mix back in. A small price to pay. I can genuinely tell the difference between Straus and supermarket brands, even after mixed with chocolate. The more fat, the greater the difference will be (the nonfat milk isn’t that different, while the cream is amazing).
You can make excellent hot chocolate with just milk and cocoa powder, as long as you use good milk and cocoa powder. By far my favorite is Scharffen-Berger cocoa powder, which has an amazing strong fresh chocolate smell and taste that will surprise those accustomed to Hershey’s. I do not like dutch-processed cocoa powder for hot chocolate (though I do prefer it for cakes).
Dagoba organic (icky), Scharffen-Berger (yummy), and Valrhona (dutch-processed) cocoa powders.
In a nice sized mug (mine’s a little over a cup), put a slightly rounded tablespoon of sugar and a piled high tablespoon of Scharffen-Berger cocoa powder at the bottom. I usually add a little vanilla extract, maybe ⅛–¼ teaspoon. Tahitian vanilla is fun to try, but you will need a little less.
Now add just a splash of tap water (something like 2 teaspoons) to the powder mixture in the mug and start mixing. It should start to come together in a mass. Hot milk or water doesn't work as well because it melts the cocoa powder. While this sounds good, it actually makes it harder to get a smooth result. Keep adding cool water in small amounts until you get a smooth paste at the bottom. If you add too much water, you'll get a bunch of floating cocoa powder blobs in liquid, and you will never get it to combine properly. (If this happens, save half of it for later and add back a fresh half of sugar and cocoa powder to get something thicker.)
Add about ⅛ cup milk to the mug and mix to blend it with the paste (it is fine to use cold milk). Adding a little bit to start out with helps the formation of a smooth mixture. Now you can dump the rest of the milk in (about one cup total) and microwave until your desired temperature is reached.
This method uses real chocolate instead of cocoa powder for extra richness and flavor. I don’t think hot chocolate is the best use of very expensive chocolate, so I usually use something less expensive. I also think the ideal cacao percentage is on the sweet side of what I would want to eat plain, about 55–65%.
Put about 2 ounces of chopped chocolate into a ~1 cup mug. No piece should be larger than an M&M for even melting, and preferably even smaller. Add about 1 tablespoon of water a microwave on high for about 20 seconds (you might have to experiment with your microwave: the idea here is to get the water almost but not quite boiling). Poke the chocolate so it all gets under the hot water but resist the urge to stir! Let it sit for 1–2 minutes.
At this point, the chocolate bits should be melted and you can slowly stir the mixture. If you did it correctly, you should get an amazingly smooth chocolate sauce which you will be unable to resist drinking down immediately and you will have to start over. (I’ll pause here so you can redo the previous steps.)
If you have some lumps that aren’t going away, microwave it 5–10 seconds longer and let it sit some more to melt. If you mixed too soon or added too much water, you will not get a perfectly smooth mixture. Better luck next time, but it should still be pretty good.
For darker, more complex hot chocolate, add about 2 teaspoons of Scharffen-Berger cocoa powder at this point to the chocolate-water emulsion and mix well. If you like it sweet or you used a darker chocolate to start out with, you can skip this step.
Add a little splash of vanilla extract (I usually do something like ⅛–¼ teaspoons, but I don’t actually measure). It’s best to do this after the chocolate mixture has been heated and cooled a bit so you don’t heat the vanilla too much—this will damage the flavor.
Now add the milk. The most important thing is to add the milk slowly and mix it well before adding more. You should start off by adding about one tablespoon of milk (cold milk is fine, but if you use hot milk, you can be more aggressive about adding it). Mix that until it is perfectly smooth again. Do this 2–3 more times, never adding more than about 50% more milk than the total volume of the emulsion so far. Once you get to about ⅓ cup you can just dump the rest of the milk in. The result should be perfectly smooth. Now just microwave it to your liking.
The idea here is to cook the chocolate emulsion with vanilla bean to infuse some of the vanilla flavor into the drink. Take ⅛–¼ whole vanilla bean and slit it lengthwise. Scrape out the seeds and add them along with the rest of the bean into the chopped chocolate and water mixture before heating.
When I do this, I usually do it on a stove with a small thick saucepan or a double boiler. Once it gets hot, the chocolate melts, and you have a smooth mixture, cook for a few minutes on low heat. You could probably also do this in the microwave by alternating heating 10–20 seconds on low and stirring for a minute.
Add the rest of the milk. At this point you can remove the vanilla bean and drink it. However, it will be even better if you let it sit in the refrigerator for a while so the vanilla and the chocolate can blend (you can make a large batch in advance and just use it as necessary). Remove the vanilla bean and reheat for consumption.
Robert Linxe in his great book La Maison du Chocolat recommends a similar procedure. He makes 6 servings using 7 ounces of bittersweet (60%) chocolate, 2 cups milk, 1 cup water, 2½ tablespoons cocoa powder, and ½ vanilla bean.
Buy a copy of Hot Chocolate by Michael Turback, which is a fun, inexpensive little book. There are lots of exciting things to try in here that you would have never thought of yourself. My favorite is Hot Chocolate à l’Orange with orange zest, cayenne pepper, nutmeg, cloves, and Grand Marnier.
French style: High-end French-style hot chocolate is usually much thicker and richer than my recipe will give you. To get this style, use either of the “real chocolate” methods above, but use 50–75% of the specified amount of good-quality whole milk. Danger: use only very small cups for serving, as more than ½ cup will likely kill you.
Flavors: Hot chocolate is great with coffee, rum, Grand Marnier, irish cream, Kahlúa, etc.
Mayan style: Mix in a pinch of cinnamon and a quarter pinch of fine chili powder to the paste before adding milk. The spiciness sounds revolting to most people but it actually goes very well with chocolate.