Here are some examples of recipes that can be made with cauliflower instead of grains and legumes:
Cauliflower rice: Replace white or brown rice with cauliflower that has been grated and then cooked.
Cauliflower pizza crust: By pulsing cauliflower in a food processor and then making it into a dough, you can make a delicious pizza.
Cauliflower hummus: Chickpeas can be replaced with cauliflower in hummus recipes.