I’ve been making pureed vegetable soups for years and the recipe just keeps getting simpler and better. When I first started making them a dozen years ago, I’d add the vegetables, along with broth and a little flavoring, to a sautéing onion–a competent, but rather uninspired concoction.

Eventually I realized that if I sautéd the vegetables along with the onion, the soup would be more flavorful, and so for a few years that became my new way. Except that since the vegetables in these soups act as both flavoring and thickener, you need a lot of them, and sautéing a lot of them in a little soup kettle takes time.

So then it occurred to me that I could save time if I simply roasted the vegetables while the onions were sautéing. And because there was so much room on that roasting pan, the vegetables browned even more impressively and produced an even more flavorful soup.

But then a few weeks ago when Maggy and I were making a cauliflower soup I got new enlightenment. This soup was such a good lesson for both of us, because Maggy came up with the brilliant idea to enrich this vegetarian soup with coconut milk (recipe to come), and it finally dawned on me that I could roast all the vegetables–onions included–and that except for heating the soup, there was no need to cook it stovetop.

I wanted to come up with an unusual version of this soup–one I had never thought of before. Not an easy task! But I started thinking about mirepoix, that little mix of celery, carrots, and onions, that is the foundation of so many of the soups and stews we all love. And how when we smell it sauteing, we start to get hungry because we know something good is to come.

Why couldn’t those three vegetables star rather than support, I thought? The onions and carrots would clearly make a fine soup, but might celery stalks make the soup too thin? But then I thought about celery in root form–a much better idea.

So here’s the recipe. It makes a very nice first course soup at a dinner party, but it’s also perfect alongside a grilled cheese. Speaking of which… see that grilled cheese in the background of the photo? It’s no ordinary grilled cheese, and we’ll be posting the recipe tomorrow.

Happy President’s Day!

Come join SoupaPalooza at TidyMom and Dine and Dish sponsored by KitchenAidRed Star Yeast and Le Creuset

Mirepoix Soup

Serves 4

1 pound each:  onions (2 large), peeled and cut into large chunks, carrots, tops trimmed and cut into large chunks, celery root (1 medium) peeled and cut into large chunks.
3 tablespoons olive oil
2 teaspoons dried thyme leaves
Salt and ground black pepper
5 to 6 cups  chicken or vegetable broth

Toss vegetables on a rimmed baking sheet with oil, thyme and a sprinkling of salt and pepper. Place on the bottom rack of a cold oven and heat oven to 425 degrees. Roast vegetables, stirring once or twice, until golden-brown and tender, 25 to 30 minutes. Working in batches, place vegetables in a blender, adding enough broth to puree until silky smooth. Transfer to Dutch oven and heat through. Serve.