You’re probably thinking of Campbell’s. And you may presume that “cream of anything” soup originated in America. It didn’t.
Long before canning was invented, and long before there was Campbell’s, the Italians and the French have been cooking soups with Béchamel sauce (a roux with milk or cream) as the base.
And that’s how our cream of mushroom soup was cooked. With a roux. But the roux is formed after grated onion, chopped mushrooms, thyme, salt and pepper had been happily swimming in the butter.
Adding the mushrooms much earlier than most cooks do coaxes out the flavor better. That means that, by the time the soup is done, it tastes of mushrooms instead of thickened milk.
And then, there’s the chicken bone broth. Most recipes use chicken bouillon or crumbled chicken bouillon cubes. But I find the aroma and flavor of chicken bouillon too artificial. I prefer chicken bone broth.
We start by grating a peeled onion. Why grate and not chop? Grated onion makes a smoother soup. I used the grater with the largest holes.
Take a few of the mushrooms and slice thinly. That will be your topping. Chop the rest. That will be cooked in the soup to give it a pronounced mushroom flavor.
Melt butter in a pan, spread the sliced mushrooms and brown a bit, flip and continue browning then scoop out and set aside.
In the remaining butter, saute the grated onion and thyme. Do this over medium-low heat with plenty of stirring to allow the onion bits to brown and caramelize a little. That caramelization is added flavor.
To the onion and thyme, we add the chopped mushrooms and more butter. We’re in the first stage of making the roux here.
Season the mushrooms and stir well before adding flour. As soon as the flour is in the pot, stir everything quickly and thoroughly to distribute it evenly.
Cook the roux for a minute to allow the flour to soak up all the butter and mushroom juices. Mix the milk with broth and pour into the pot in a thin stream.
Without covering the pot, cook the soup, stirring often, until thickened. Note that the soup will appear thin at first but, as it simmers, it will thicken little by little. Stop when the soup coats the back of a spoon. Taste to make sure it leaves no powdery sensation on your tongue. Taste and adjust the seasonings one last time.
Your cream of mushroom soup is now ready to be served. Ladle into bowls, top with the reserved sliced mushrooms and, if you want to add color and flavor, chopped greens. Parsley is a popular choice but we discovered that aonori (Japanese dried seaweed) is superb with this thick and creamy mushroom soup.
Cream of mushroom soup
- Peel the onion and grate until you have a quarter cup.
- Take four to six mushrooms and slice.
- Chop the rest of the mushrooms.
- Melt four tablespoons butter in a pot and spread the sliced mushrooms. Cook for a minute then flip to lightly brown the opposite sides.
- Scoop out and set aside.
- Saute the grated onion and dried thyme in the remaining butter in the pan.
- Add the chopped mushrooms and the remaining two tablespoons butter.
- Season with salt and pepper and cook, stirring, for about a minute.
- Add the flour and stir quickly.
- Cook, stirring constantly, for a minute or so.
- Whisk the milk and broth together, and pour into the pot in a thin stream, stirring as you pour.
- Cook uncovered over medium heat (to prevent the milk from curdling), stirring often, until thick (it should coat the back of a spoon) and the soup leaves no flour-y sensation in the mouth.
- Taste. Depending on how well seasoned the chicken broth is, you may need to add more salt and pepper.
- To serve, ladle your real cream of mushroom soup into bowls and top with the sliced mushrooms.