French Onion Soup is, for something so inherently simple, an amazing combination of flavors and textures.
Done right, French Onion Soup is one of the biggest pay-off dishes you can possibly make. That first bite of bubbly-brown gruyere, loaded on top of oozing swiss and still crispy crouton, dripping with flavorful broth and caramelized onions. It’s almost too much.
It’s popular as an appetizer, but there’s enough there for a simple meal. And there’s no reason you can’t prepare the components ahead of time and re-heat at the point of assembly. Even the crostini can be made a couple of days ahead if needed. You can also leave out the port, although it looses most of the alcohol in reducing and simmering, and the flavor will be altered without it. Just replace it with an equal amount of beef stock.
Make sure you use a pan with a lot of bottom surface area to caramelize the onions. The more contact the onions have with the bottom of the pan, the more chance it has to develop the brown caramelization that is the magic of this soup. It just takes a little patience, but what it does to the onions is crucial.
Cut both ends off the onions and slice in half lengthwise.
Peel, and julienne slice from root to tip into 1/4 inch slices. When you are caramelizing onions you need thicker slices, otherwise they will just melt away.
In a large, wide and heavy-bottomed pan, heat the olive oil and butter together until butter begins to sizzle. Add the onions and toss into the oil/butter mixture just to coat. Sprinkle the kosher salt over the onions. The salt will season and assist in caramelization.
On medium-high heat, let the onions cook and begin to brown. Do not over-stir. Just move the onions around barely enough to keep them from burning. Continue this process, letting onions brown and soften, stirring only to keep onions from burning and sticking to much to the bottom of the pan. This will take anywhere from 20-30 minutes, depending on the thickness of the onions. As with many dishes, the longer you take to caramelize, the more flavor you will be adding to the finished product. Sometimes you will get a hot spot, so rotate your pan around as well. If you do get a spot that appears to be over-browning, add an 1/8 cup of water and deglaze that area. You want nice, deep-brown action, but you DON'T want BURNT! This will affect your entire dish!
Once the onion are caramelized and softened (see photo), and the pan is still good and hot, add the port.
Stir and loosed the browned bits from the bottom and sides of the pan. This is de-glazing. You are incorporating the caramelization that has occurred on the bottom of the pan (flavor!), as well as reducing the liquid added. If you choose not to use port, add an equal amount of beef stock/broth instead to deglaze. Let liquid simmer until reduced by half. This should only take a few minutes.
Next, add the garlic slices, the beef stock/broth, and the thyme and bayleaf. Simmer for 20 minutes on medium heat.
In the meantime, prepare the crostini.
Slice the baguette into slices about 1/2 inch thick. Slice them on the bias--this means on an angle, as this will give you slices with more surface area. Depending on the size of the crostini, and the size of your serving dishes, you will need 12-24 crostini. You want the whole surface of your soup covered. Make a few extra, it won't kill you.....
Drizzle a little olive oil over each slice, and season with salt and pepper.
Place on a baking sheet and bake in a 350 degree F. oven for 10-15 minutes, flipping over halfway. You want these crostini nicely browned and CRISP! all the way through, as they will be trying their best to soak up the awesome onion soup. You don't want them too soggy too fast!
Let them cool and divide the goat cheese between the slices, spreading a layer of cheese on each.
Finish the soup off by adding the beef and chicken base. Salt and pepper to taste. Remove the thyme sprigs and bay leaf and discard.
When ready to serve, preheat the oven to broil.
Place your oven-safe containers onto a baking dish to catch drips and make transporting soup easier. Ladle the hot soup into oven-proof bowls, cups, or ramekins.
Arrange 2-4 cheese covered crostini over the top of the soup, cheese side up.
Lay two slices of swiss over the top of the croutons and the bowl. I like to let the slices overlap the edge of the dish. It keeps the grated cheese from falling down into the soup, and looks seriously cool when all brown and gooey.
Divide the grated gruyere over the six bowls, sprinkling an evan layer over each.
Place the bowls into the oven, about 6 inches from the broiler and let broil until cheese is brown and bubbly, about 1-2 minutes. Garnish with chopped fresh flat-leaf parsley.
Serve immediately, letting guests know that the soup is ridiculously hot, but that they should eat it as soon as the danger of serious burning has passed, because half the pleasure from French onion soup lies in the texture differences.