Chop cauliflower into small chunks and pulse through a food processor until it looks like grain. Do not over-do it or you will puree it. You can also grate the whole head with a cheese grater if you don't have a food processor.
Microwave for 8 minutes for a whole large head. No added water. The moisture in the cauliflower will cook itself.
Combine all ingredient except the melted butter.
Form the crust on a cookie sheet.
Brush the top with melted butter - sprinkle with garlic powder/salt if desired.
Bake at 400 for 10 minutes, then lower to 350 and cook for an additional 20 minutes.