It’s snowing again. I lost my scraper in my recent move, so I had to clean off my car this morning with a snow shovel leaned against the side of the house. Times like this are the second best time for a steaming mug of thick hot chocolate.

Problem is, it’s always disappointing to fire up your cocoa, take a luxurious sip, then get distracted by YouTube videos of breakdancing raccoons. Before you know it, your hot chocolate is cold, and throwing it in the microwave isn’t the same as having it fresh.

The best solution to this problem is to make hot cocoa that is so good that it can’t be forgotten. However, the second best solution is super simple: make hot milk foam.

Milk is mostly composed of water, which is a fantastic insulator. However, milk is also composed of proteins and sugars (i.e. lactose) that create a semi-rigid structure. Put differently, you can whip milk up into a foam that acts like a warm little hat for your coffee mug. That hat will slow down your drink’s heat loss, prolonging its period of steamy warmth and also adding a fun texture to the top layer of the drink.

How to Make Milk Foam

If you’re a hardcore tea, coffee, or hot chocolate drinker, you might consider buying a milk frother for about $10. However, it’s not necessary. Here’s my method (taken from the incredible food science book, On Food and Cooking) for making milk foam.

What you’ll need:

• Mason jar with lid
• Fresh milk
• Microwave

How to make the foam:

1. Pour some milk into your mason jar until it is about ⅓ full. You want plenty of air in that jar. Then screw the lid tightly onto the jar.
2. Shake it. Play Hey Ya! by Outkast on repeat and shake that jar like it’s a cynical Cook’n elf having an existential crisis. The milk will eventually expand into a foam. Keep shaking until you’ve reached your desired consistency.
3. Take off the jar’s lid and heat the milk in the microwave for thirty seconds.
4. Remove the jar from the microwave and pour it over your waiting cup of steaming mojo.

Note: skim milk is more efficient than whole milk for making a foam, but either will do if you don’t buy skim milk (I sure don’t).

Another note: fresh milk is best for making foam because its proteins are in an ideal state to form into a good froth.

Final note: no, your milk foam will not make your hot chocolate stay hot for hours on end. But it will extend its shelf life, and it’ll also add some fun texture to the top of the mug and make you look like a culinary wizard.

I hope this article makes you excited to have another snow day.