Soup enhanced by an herbal infusion

Rosemary-infused olive oil sets this easy cauliflower soup apart from its brethren. This recipe has you heat and steep four herb sprigs in oil as you cook the cauliflower in an aromatic-enhanced stock for the soup.

You don’t have to make the croutons, but their crisp contrast is a nice touch.

Creamy Cauliflower Soup With Rosemary Olive Oil

Makes 6 servings

FOR THE ROSEMARY OIL:
1 cup olive oil
4 (4-inch) sprigs fresh rosemary

FOR THE SOUP:
2 tablespoons olive oil
1 medium yellow onion, chopped (about 1 cup)
2 garlic cloves, minced (about 1 tablespoon)
1 quart low-sodium vegetable stock, plus more as needed for reheating
1 medium head cauliflower, cored and broken into 1½-inch florets (about 2½ pounds)
2 teaspoons kosher salt (such as Diamond Crystal), plus more to taste
1 teaspoon black pepper, plus more to taste
Freshly grated zest of 1 lemon, for serving

FOR THE CROUTONS (optional):
3 cups diced rustic country bread (¾-inch pieces)

Make the rosemary oil: In a medium skillet, combine the olive oil and rosemary sprigs. Cook over low heat for 5 minutes, lowering the heat if the oil reaches a full simmer. (You want to cook it at a very gentle simmer to avoid frying the rosemary.) Carefully pour the oil and rosemary into a small bowl, leaving a slick of oil in the pan if you plan to make croutons. Allow the rosemary to cool completely in the oil while you make the soup.

Make the soup: In a heavy pot or Dutch oven, heat 2 tablespoons olive oil over medium-low. Add the onion and cook, stirring occasionally, until tender and translucent, 6 to 8 minutes. Add the garlic and cook until fragrant, about 30 seconds. (Be careful not to let the garlic scorch!)

Add the stock, cauliflower, salt and pepper, and bring to a boil over high. Lower the heat, cover, and simmer until the cauliflower is tender when pierced with a fork, about 10 minutes.

Meanwhile, make the optional croutons: Heat the reserved skillet with the residual rosemary oil over medium. Add the bread cubes, sprinkle generously with salt and pepper, and cook, tossing often, until toasted all over, 4 to 5 minutes. Transfer the croutons to a plate or board to cool.

Strain and discard the rosemary stems from the rosemary oil. Working in batches if necessary, carefully transfer the vegetables, stock and ¼ cup rosemary oil to a blender and blend on high until creamy. Add more rosemary oil to taste, and blend to combine. Return the soup to the pot and bring to a simmer. If the soup seems thin, let it simmer for 5 to 10 minutes to reduce slightly. (Remember: The soup will continue to thicken as it cools.) Season to taste with salt and pepper.

Serve hot. Garnish each serving with a swirl of rosemary oil, a few croutons, and a sprinkle of lemon zest. The soup will thicken as it sits; add more stock as necessary when reheating. Leftover rosemary oil will keep in a sealed container at room temperature for up to 1 week.

Heuck is a freelance writer. This article appeared in The New York Times.