Set a steamer basket in a saucepan with 2 inches simmering water. Add cauliflower; cover and steam until very tender, 18 minutes. Transfer cauliflower to a food processor and season with salt and pepper. Add broth and process until smooth, scraping down side as needed (add more broth for a thinner consistency, if desired). To serve, transfer to a bowl, season to taste with salt and pepper, and drizzle with olive oil. Puree can be refrigerated in an airtight container, up to 3 days.