In stockpot over medium-high heat, heat oil. Add onion and garlic. Saute until onion is translucent, 3 to 5 minutes.

Reduce heat to medium. Add flour. Whisk until well blended. Cook, whisking often, 4 minutes. Do not brown.

Add broth, curry powder, salt and pepper. Whisk until well blended. Cook, whisking constantly, until mixture thickens and boils.

Add cauliflower. Return to a boil. Reduce heat. Simmer, stirring often, until cauliflower is very tender, 30 to 35 minutes.

In blender, blend soup until smooth, 3 to 5 minutes.

Cover. Keep hot for service.