When summer is in full swing and the markets are loaded with good-looking vegetables, I’m never at a loss for what to do with them. Gratins, sautés, salads, grilled vegetables with aïoli—these are my summer standbys. But after a while, I start to crave something just a little bit off the beaten track, and that’s when my thoughts turn to puréed vegetable soups—nothing captures the essence of a season better. Creamy, smooth, and full of flavor, puréed soups go down easy on a warm day. They’re a perfect first course for company. Just top with a tomato relish, a yogurt drizzle, or a swirl of olive oil or sour cream and you’re set to go.
If you’ve made puréed vegetable soups before, you’ve probably enriched them with cream and thickened them with potato, rice, or flour. This is where I break with tradition. I omit these in favor of a soup that’s perhaps slightly lighter in body but that has a more pure and intense flavor and is no less smooth.
Here are the five basic steps to making delicious puréed soups
You can follow my recipes for corn, summer squash, and eggplant soups, but the following technique works with many other vegetables, such as artichokes, broccoli, carrots, green beans, spinach, Swiss chard, and winter squash.
1. Make a fifteen-minute broth with tender fresh herbs. I use a generous handful of delicate herbs like basil or cilantro or flavorful parsley stems, which willingly surrender their flavors and aromas to a boiling pot of water or chicken broth. I might also add a few thyme sprigs, a bay leaf, a garlic clove, or any aromatic ingredient that I suspect would give the soup a pleasing, complementary backdrop of flavor (for a corn soup, I’ll toss in the corn cobs once I’ve cut off the kernels). A mere fifteen minutes of simmering might seem like it would make a weak broth, but you’ll be surprised how quickly you can extract flavor from these ingredients, especially those tender herbs.
While the broth is simmering, start cooking onions in a saucepan with butter or olive oil. Usually, I cook the onions just long enough to soften them and draw out their juices—a technique that’s called sweating—though sometimes I cook them longer to get the deeper flavor from browning. Along with the onions, I might add aromatic flavorings like ginger, chile, or spices. Add minced garlic only after the onions are cooked so that it doesn’t burn.
2. Cook the vegetable, either separately or in the broth. I’ll roast eggplant and I’ll cook summer squash briefly with the sweated onions, but I usually just add corn kernels straight to the broth. It depends in part on the vegetable and in part on my mood. You could also grill the vegetable for a suggestion of smokiness in the soup. Whether it’s raw or completely cooked ahead, the vegetable always needs at least a few minutes of simmering with the herb broth to let the flavors merge.
3. Blend the vegetables in batches to get a smooth purée. I find that a blender is more effective than a food processor for shredding vegetable fibers and getting a more emulsified purée. An important safety precaution for puréeing hot vegetables is to remove the center cap crack the lid slightly, and then lay a towel on top before starting to blend. This prevents a sudden burst of air pressure from pushing the lid off and spewing hot liquid. Also, start with a small amount of vegetables and blend in pulses or on a low speed at first. Once the vegetables in the blender are liquefied, you can ladle in more vegetables through the feeder cap with the blender running.
Since I don’t add any thickener to these soups, it falls to the vegetable itself to supply a sense of fullness and body. You need some broth in the blender to purée the vegetables, but don’t add more than what’s necessary; watery vegetables like zucchini won’t need any added broth at all. You can always add more broth later if the soup is too thick, but if you add too much too soon, you’re stuck.
4. Push the purée through a fine sieve for a satiny texture. Straining out tiny vegetable fibers takes the soup from pleasantly smooth to elegantly silky. Without any cream to gloss over the rough spots, these soups really benefit from the sieving.
5. Stir in garnishes for a visual lift. An unadorned bowl of puréed soup has a simple if understated beauty, but that doesn’t keep me from dressing it up and adding another layer of flavor at the same time. Little touches play big. Try a spoonful of sour cream, crème fraîche, or yogurt for a cool tang, a drizzle of fruity or peppery extra-virgin olive oil for richness, or a handful of homemade croutons for contrasting texture. For a bigger flavor impact, make the roasted red pepper coulis, raita, or tomato relish in the recipes here.
Puréed vegetable soups will hold up for a few days in the refrigerator, but they sometimes separate. To bring them back together, whisk them vigorously or use an immersion blender.