Pureed cauliflower lends a creamy, silky texture to this vegetarian white bean soup without using a drop of dairy.
Preheat oven to 400°F.
Heat 2 tablespoons oil in a large pot over medium heat. Add onion and cook, stirring often, until softened, about 5 minutes. Add garlic and 1 teaspoon each sage and thyme; cook until fragrant, about 1 minute. Stir in cauliflower, broth, beans, pepper and salt. Bring to a boil. Reduce heat to maintain a simmer, cover and cook until the cauliflower is very tender, 15 to 20 minutes.
Meanwhile, spread bread on a rimmed baking sheet and bake until golden brown, about 10 minutes. Transfer to a medium bowl and toss with 1 tablespoon oil and the remaining 1 teaspoon each sage and thyme.
Puree the soup using an immersion blender (or in batches in a regular blender) until smooth. (Use caution when blending hot liquids.) Serve the soup with the croutons and drizzled with the remaining 1 tablespoon oil and sprinkled with more thyme, if desired.
To make ahead: Refrigerate soup for up to 3 days.