Cauliflower can be anything, including gravy. I LOVE Alex Snodgrass's Cookbook and Blog, The Defined Dish. Her cookbook is one I probably use the most out of the collection that I have, and this recipe is the closest and best white gravy recipe I've found that is GF & DF.
I use her recipe exaclty, so I copied it for you below!
2 tablespoons ghee
1 cup diced yellow onion (1 medium)
1 teaspoon kosher salt
½ teaspoon dried thyme
4 cups fresh cauliflower florets (1 large head)
2 cups low-sodium chicken broth
1 teaspoon freshly ground black pepper
In a large saucepan over medium heat, melt ghee. Add onion, salt, and thyme and cook until onion is tender, 3 to 4 minutes. Add cauliflower florets and broth and bring to a boil. Reduce heat to a simmer, cover, and cook until cauliflower is fork-tender, about 15 minutes. Transfer mixture to a high-powered blender and blend until very smooth. Stir in black pepper. Cover and keep warm until ready to use.