There's something about a bubbly melty crock of french onion soup that warms my insides, even when I'm not eating it. I feel that I'm always craving it, something about the saltiness of the broth, the sweet of the onions, the crunch of the toasted baguette, the stringiness of the cheese.. it all comes together to create a savory mix of flavors and textures that can't be beat on a cold winter day. Luckily, it is EXTREMELY easy to make, just requires some time to render all the flavor out of the ingredients.
The key to a good french onion soup is to caramelize your onions low and slow for a LONG time. You want them to be deep brown in color, but not burnt, and completely soft and melty. In another pot, you'll want to sear some beef bones with onions, garlic, thyme and bay leaves, deglaze with water and some red wine, and let the broth-to-be simmer for an hour or two, then strain.
Once you have the rich caramelized onions and deeply beef-flavored broth, you can THEN combine the two, ladle into your oven-safe crock, top with a slice or two of a toasted french baguette, cover in shredded gruyere, and broil until the cheese starts bubbling and freckling. Top with chives to get one last level of onion flavor into the soup and enjoy!