Brush on roasted chicken, drizzle over winter vegetables, or sop it up with a slice of bread.
This vegan soup will keep you toasty all autumn long!

INGREDIENTS

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 1.5-inch florets
(about 2.5 pounds)

2 teaspoons Kosher salt, plus more to taste

1 teaspoon black pepper, plus more to taste  

Freshly grated zest of 1 lemon, for serving

PREPARATION

• 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 heat. 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 heat. 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 1/4 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 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.