Fill a large pot with warm water. Place the sous vide into the pot and set temperature to 185 degrees F (85 degrees C) and timer for 50 minutes.
Combine Cajun seasoning, celery salt, chili powder, garlic granules, and onion powder in a small bowl. Place cauliflower in a mixing bowl, add the spice mixture, and stir to coat. Drizzle in oil and mix until well combined. Pour cauliflower into a sous vide bag and vacuum-seal.
Submerge bag in the pot when the temperature reaches 185 degrees F (85 degrees C) and cook until timer ends. Remove from bag and serve.
