In a microwave-safe bowl, add onions, celery, carrots, olive oil, cayenne pepper, and thyme.
Microwave for 3 minutes and then stir, cook another 3 minutes. Transfer to the slow cooker.
Add 3 cups of cauliflower florets to a microwave-safe bowl. Add ¼ cup water and cover tightly with plastic wrap. Microwave for 5 minutes, or until florets are tender.
Drain the cauliflower and add to a blender.
Add in 1 ½ cups corn and 2 cups chicken stock. Blend until smooth, about 1 minute. Transfer to the slow cooker.
Add 1 cup chicken stock, chicken breasts, red potatoes, milk, salt, and bay leaf to the slow cooker. Stir to combine all ingredients. Cover and cook until vegetables are tender; 3 to 4 hours on High setting or 5 to 6 hours on Low.
Discard bay leaf. Remove chicken and shred into smaller pieces.
Stir in remaining 1 ½ cups corn and shredded chicken, let it sit until heated through, about 10 minutes on High setting.
Taste and season with salt and pepper as desired. Stir in 1 tablespoon parsley and serve hot. Top with additional parsley and pepper.
Optional Toppings: Bacon and sauteed cauliflower.
MAKE IT DAIRY-FREE: Replace 1 cup of milk with additional chicken broth, unsweetened cashew milk or coconut milk (this may alter the flavor more than the other alternatives).