1stalkof lemongrass, tough outer layers removed, bottom inch and tapered top removed, finely chopped
1 ½cupsof coconut milk
1tablespoonof tomato paste
2smallThai bird chiles (or 1 serrano chile), halved, seeds removed if you want less heat
1 ½tablespoonsof lime juice
1 ½teaspoonsof kosher salt (or ¾ teaspoon table salt)
cilantro leaves, finely chopped scallion, olive oil, and sriracha as garnish
Preheat the oven to 400 degrees F (204 degrees C). Line a baking sheet with aluminum foil. Cut the butternut squash in half lengthwise. (Microwaving the squash for a minute or two can help soften it up and make it easier - and safer - to cut in half. If you do microwave it, be sure to give the skin a few good stabs with the tip of your knife so nothing ends up exploding all over the inside of your microwave.) Prick the skin of each half a bunch of times with a fork, scoop out the seeds and stringy bits, then give all surfaces a quick spray with cooking spray. (Or brush lightly with some oil.) Place cut-side down on the baking sheet, and bake for 40 minutes. Remove from the oven, let cool, and scoop the flesh out of the skin, place in a bowl, and set aside. (You only need half the squash for this recipe, but it never hurts to have half a cooked squash on hand.)
Heat the oil in a pot over medium-high heat. Add the onion, and saute until softened, 5-8 minutes. Add the squash, garlic, ginger, lemongrass, coconut milk, and tomato paste, bring to a boil, and simmer until everything is heated through, around 10 minutes. Transfer to a blender (in batches, if necessary), add chiles, lime juice, salt, and water, and puree until smooth. (Alternately, add the chiles, lime, salt, and water to the pot, and puree with an immersion blender.) Return to the pot, adjust seasoning, and reheat until ready to serve. Transfer to bowls and garnish with cilantro leaves, chopped scallions, and drizzles of olive oil and sriracha.
A good garnish – which I didn’t do but occurs to me now, having done it before with other squash soups – is to toast the squash seeds in a little oil and then sprinkle them over the top, along with the sriracha, cilantro, scallion, and olive oil.