Place the cauliflower, carrots, and celery in a bowl or mason jar.
Shake the borscht, mixing up the beet liquid and beet pieces and measure out one cup. In a small saucepan, bring the borscht, vinegar, and salt to a boil. Once it reaches a boil, turn off heat and pour over cauliflower and vegetables.
Cover and let sit in the fridge for two days.