Break the cauliflower into florets. Place in a roasting tin and drizzle with 1 tablespoon olive oil.
Roast in the oven for 20 minutes, then stir and replace in the oven for a further 10-20 minutes until cooked through and turning golden brown.
Remove from the oven and allow to cool.
When cool place in a blender or food processor with 250ml dairy free milk, 2 tablespoons of nutritional yeast, 1 teaspoon of onion powder and a teaspoon of tapioca starch (or cornflour). Season with a little salt and pepper.
Blend until smooth. You may need to stop to scrape the sides down.
Taste and adjust the seasoning if needed.
Transfer to a saucepan and reheat, stirring often. The sauce will thicken as you reheat it.
Serve with pasta or as an alternative pizza sauce.