When considering uses for sturdy greens like kale and Swiss chard, a smooth pureed soup may not immediately come to mind. But we had high hopes for a silky-smooth soup that delivered a big dose of healthy greens packed with essential nutrients.
First, we built a flavorful foundation of sweet caramelized onions and earthy sauteed mushrooms. We added broth, water and lots of leafy greens (we liked a mix of chard, kale, arugula, and parsley, each with unique nutritional qualities), and simmered the greens until tender before blending them until smooth.
We were happy with the soup's depth of flavor, but it was watery and too thin. Many pureed soups call for excessive amounts of cream to create a velvety consistency.
Instead, we used Arborio rice: The rice's high starch content thickened our soup perfectly and without dulling the bright flavors of the greens. And rather than adding dairy richness by the cupful, we drizzled each bowl with just a tablespoon or two of yogurt enlivened with lemon and tarragon.
Super greens soup
Start to finish: 1 hour, 20 minutes
1/2 cup organic plain low-fat yogurt
2 tablespoons plus 1/2 teaspoon cold-pressed extra-virgin olive oil
1/2 teaspoon minced fresh tarragon
1/4 teaspoon finely grated lemon zest plus 1/2 teaspoon juice
Salt and pepper
1 onion, halved through root end and sliced thin
3/4 teaspoon light brown sugar
3 ounces white mushrooms, trimmed and sliced thin
2 garlic cloves, minced
Pinch cayenne pepper
3 cups water
3 cups homemade or low-sodium chicken or vegetable broth
1/3 cup Arborio rice
12 ounces Swiss chard, stemmed and chopped coarse
9 ounces kale, stemmed and chopped coarse
1/4 cup fresh parsley leaves
2 ounces (2 cups) baby arugula
Combine yogurt, 1/2 teaspoon oil, tarragon, and lemon zest and juice in bowl. Season with salt and pepper to taste, cover, and refrigerate until ready to serve.
Heat remaining 2 tablespoons oil in Dutch oven over medium-high heat until shimmering. Stir in onion, sugar, and 1/2 teaspoon salt and cook, stirring occasionally, until onion releases some moisture, about 5 minutes. Reduce heat to low and cook, stirring often and scraping up any browned bits, until onion is deeply browned and slightly sticky, about 30 minutes. (If onion is sizzling or scorching, reduce heat. If onion is not browning after 15 to 20 minutes, increase heat.)
Stir in mushrooms and cook until they have released their moisture, about 5 minutes. Stir in garlic and cayenne and cook until fragrant, about 30 seconds. Stir in water, broth, and rice, scraping up any browned bits, and bring to boil. Reduce heat to low, cover, and simmer for 15 minutes.
Stir in chard, kale, and parsley, 1 handful at a time, until wilted and submerged in liquid. Return to simmer, cover, and cook until greens are tender, about 10 minutes.
Off heat, stir in arugula until wilted. Working in batches, process soup in blender until smooth, about 1 minute. Return pureed soup to clean pot and season with salt and pepper to taste. Drizzle individual portions with lemon-tarragon yogurt, and serve.
Nutrition information per serving: 152 calories; 52 calories from fat; 6 g fat (1 g saturated; 0 g trans fats); 0 mg cholesterol; 388 mg sodium; 20 g carbohydrate; 3 g fiber; 5 g sugar; 7 g protein.