Preheat the oven to 450 degrees F.
Line two baking sheets with parchment paper. Toss the cauliflower with the coconut oil in a medium bowl. Add the nutritional yeast, marjoram, thyme, granulated onion and cayenne and sprinkle with salt and pepper. Mix well, then spread the cauliflower out evenly on the prepared baking sheets. Roast, tossing once halfway through, until the cauliflower is well-browned and a little crispy, about 30 minutes. Allow to cool a few minutes before serving.