Ingredients

• 1 head cauliflower, cut into florets
• 2 tablespoons olive oil
• 2 teaspoons curry powder, or more to taste
• 2 teaspoons mustard seeds
• 5 tablespoons butter, divided
• 1/3 cup chopped sweet onion
• 6 cups chicken broth
• 3 tablespoons all-purpose flour
• 1 cup milk
• salt and ground black pepper to taste

Instructions

1. Preheat oven to 350 degrees F (175 degrees C).
2. Combine cauliflower, olive oil, curry powder, and mustard seeds in a baking pan; toss to coat cauliflower.
3. Bake in the preheated oven until cauliflower begins to brown, 35 to 40 minutes.
4. Heat 2 tablespoons butter in a saucepan over medium heat; cook and stir onion until softened, 5 to 10 minutes. Add chicken broth and cauliflower to onion; bring to a boil. Reduce heat to low and simmer.
5. Combine 3 tablespoons butter and flour in a small saucepan over medium-low heat; cook and stir until roux is thickened and slightly browned, about 5 minutes. Add milk to roux and continue cooking and stirring until thickened, 5 to 10 minutes. Stir roux into soup until smooth; season with salt and pepper.