Preheat oven to 425 degrees and line a baking sheet with parchment paper.
Place cauliflower florets in a large bowl. Pour the vinegar over the cauliflower and toss to combine. Set aside and let marinate for 15-20 minutes.
Combine flours, salt and pepper in a large storage container or ziplock bag.
Using a slotted spoon, remove cauliflower, draining excess vinegar and place in the container with the flour mixture. Cover or close container/bag and shake until all the florets are coated with the mixture.
Spread cauliflower out onto baking sheet in an even layer.
Bake for 20 minutes, flip gently using a large spatula and continue baking for another 20-25 minutes until crispy and golden brown.