I’ve had a couple tubs of Thai curry paste kicking around in my fridge since the summer. But when butternut squash came into season this year, I started putting them into heavy rotation. I love butternut squash soup as it is, but lately I’ve been liking my winter squash on the spicy side. So I make a very simple soup–just leeks, garlic, ginger, and squash, plus enough broth to make it soupy–and add a little dollop of curry paste. Squash loves curry in all forms, and its sweetness really welcomes the spiciness of Thai curry. It makes for a really terrific soup.
I’ve used red and green curry here, and they were both great. The red curry is a cleaner, sourer heat, and I find I need a little less paste to do the job. Green curry is richer, darker, maybe slightly less spicy, and I use a little more of it to really zing. In either case, the effect is both surprising and subtle: lots of fire up front and a quiet thrum of curry in the background.
The soup is nice enough on its own, but adding a little pile of fried shallots to each bowl really makes it special. Pureed squash can be a bit sugary and boring on its own, and the fried shallots add a lovely crackly-crisp texture and bittersweet contrast that I just love. If you’re serving the whole batch of soup at once, I’d suggest frying all the shallots right in the soup pot, then using the shallot-infused oil to make the soup. But if, like me, you like making soup ahead of time and freezing it for later, just fry up a little batch of shallots whenever you’re ready to eat.
I’m not normally one for adding cream to pureed soups, but this soup really benefits from something rich stirred in at the end. The curry paste I use is very spicy, and it needs a bit of fat to tame it so that the other flavors come through. Coconut milk is the obvious choice, but I don’t always want to open a whole can just to use a drizzle. I’ve finished this soup with different dairy and non-dairy milks, depending on what was in my fridge at the time, and it comes out great every time. The recipe includes a bunch of options; use what you like, or what you’ve got on hand. It’s that kind of soup.
Thai Curry Butternut Squash Soup with Fried Shallots (serves 4)
Adapted loosely from Williams-Sonoma
Note: I use Mae Ploy brand curry paste, which contains shrimp. The soup can easily be made vegan by using a vegetarian curry paste and non-dairy milk.
1 tbsp coconut, peanut, or vegetable oil
1 large or 2 small leeks, white and light green parts only, washed and thickly sliced
Salt to taste
1 tbsp minced or finely grated fresh ginger
2 large or 4 small garlic cloves, minced
1 quart (4 cups) vegetable broth
1-3 tsp Thai curry paste (red, yellow, or green), to taste
1 1/2 – 2 lb butternut squash (about 1 medium squash), peeled, seeded, and cut into 2-inch cubes
To finish the soup:
2 medium shallots
1 tbsp coconut, peanut, or vegetable oil
1/2 cup heavy cream, half-and-half, coconut milk, almond milk, or plain yogurt, or to taste
1 tbsp freshly squeezed lime juice (about half a lime’s worth), or to taste
Chopped fresh cilantro or Thai basil for garnish (optional)
In a large stockpot, heat olive oil over medium heat. Add leek and a pinch of salt and sweat for about 5 minutes, or until translucent. Add ginger and garlic and cook, stirring frequently, for another 30 seconds to a minute, or until fragrant. Add vegetable broth, curry paste, and squash. Bring to a boil, then reduce the heat to keep at a steady simmer. Cover and simmer for 30-40 minutes, or until the squash is completely tender.
Puree the soup using an immersion blender, or transfer to a blender and puree in batches. Cover and let stand for 15 minutes to let the flavors mingle. (You can also let the soup cool completely, then transfer it to an airtight container and refrigerate or freeze it–see instructions at the end of the recipe.)
When you’re ready to serve the soup, thinly slice the shallots and separate the slices into rings. Heat oil in a small frying pan or skillet over medium-high heat. Fry the shallot rings, stirring frequently, for about 5 minutes, or until the shallots are deeply browned and crisp. Remove the shallots from the pan with a slotted spoon and set on a paper towel-lined plate to drain. Reheat the soup and stir in cream or milk and lime juice, then season with salt to taste. Ladle into bowls and top with fried shallots and herbs.
Make ahead/leftovers: Like most curry-type things, this soup gets even better with time. It will keep in an airtight container in the refrigerator for up to a week, or in the freezer for up to 3 months. Wait to add the lime juice and the cream or milk until just before serving.