Stovetop Cooking Method: Cut the cauliflower into florets and place into a large pot. Add enough chicken stock (or salted water) to the pot to cover the cauliflower (about 4 cups). Bring to a boil over high heat, then reduce the heat and simmer, covered, for about 10-15 minutes, or until a fork can easily pierce cauliflower. Once the cauliflower is tender, strain in a colander.
Crockpot Cooking Method: Spray the crockpot with cooking spray. Add the cauliflower to the crockpot. Add enough chicken broth (or enough salted water) to cover the cauliflower (about 4 cups). Cover and cook on high for 3-4 hours or on low 6-8 hours. Once the cauliflower is tender, strain in a colander.
Meanwhile, add the onion and garlic to a small pan, (or the pot used to cook cauliflower if you followed the stovetop method). Saute onions over medium heat until golden brown.
Add cauliflower back to the pot with the onions and garlic (or add everything back to the crockpot), along with the cream cheese and parmesan. Use a handheld mixer or a hand held immersion blender (for a creamier smoother texture) to whip everything together, until cauliflower reaches a creamy texture and cheeses are melted.