Place cauliflower florets and broth in a large pot. Cover and bring to a boil over medium-high heat. Once the broth boils, reduce the heat to medium and cook until the cauliflower is very tender (about 10-15 minutes). Reserve ¼ cup of the broth from the pot; drain the cauliflower.
Transfer the cauliflower to a food processor.
Meanwhile, heat olive oil in a small skillet over medium heat. Add the garlic; cook and stir until garlic is softened, about 2 minutes. Remove from heat and discard garlic.
Process the cauliflower, adding the reserved broth, the sour cream, and the garlic-infused olive oil a little bit at a time until the mixture is smooth. Fold in the Parmesan cheese and chives; season with salt and pepper to taste.
Notes
Roasted Cauliflower Mash: You can roast the cauliflower in the oven to give it a nuttier, bolder flavor. I find that the puree is smoother and creamier, however, when the cauliflower is cooked in broth on the stovetop.
Cauliflower Mash with Cream Cheese: Swap out the sour cream and use cream cheese instead. You'll need about 2-4 tablespoons of cream cheese, depending on how thick and rich you like the puree. Make sure the cream cheese is at room temperature (or warm) so that it blends smoothly into the cauliflower.
Loaded Mashed Cauliflower: Top your cauliflower mash with all of your favorite baked potato toppings -- including butter, chives, grated cheddar, additional sour cream, and crispy bacon!
For a stronger garlic flavor, you can puree the garlic clove right into the cauliflower, rather than removing the clove from the infused olive oil.