Steam or cook the cauliflower until done. Transfer to a mixing bowl and stir in the rice vinegar and the stevia to taste. Start small and add more as needed.
Lay out a single sheet of nori.
Spread half the cauliflower onto about three quarters of the nori.
Put half of the avocado slices down.
Wet the empty edge of the nori with a little water using your finger.
Roll up the nori like a carpet, making sure to press the wet end against the roll. I usually make sure my roll rests on the open edge to make sure it glues itself together.
Slice the rolls into slices and serve with a small amount of soy sauce or tamari. (coconut aminos for those who don't do soy)
Note: use caution when slicing. The nori will move or tear easily. I found a serrated knife works best.
Notes
Please note that the nutrition data below is a ballpark figure. Exact data is not possible.