In a small bowl, add the curry powder, turmeric, coriander, cardamom, and salt. Stir to combine.
In a large slow cooker, add the coconut milk and place the chicken breasts on top.
Add the water, seasonings, and garlic to the slow cooker and stir to combine.
Add the sweet potatoes and onion to the slow cooker and place the lid on the slow cooker.
Set to low 6-8 hours or high 4-6 hours.
Forty minutes before curry is done, preheat the oven to 425 degrees F and line a baking sheet with foil. Cut the cauliflower into florets. Toss with olive oil, and a sprinkling of salt and pepper. Spread out onto the baking sheet and bake for 25 minutes.
Twenty minutes before curry is done, remove the chicken breasts and shred. Return chicken to curry and stir to combine.
Once cauliflower is done, add into the curry and stir to combine. Cook for an additional 5 minutes.
Serve curry with cilantro, if desired.