In a large saucepan, cook the cauliflower until soft and the florets are easy to pull apart (at least 15 minutes).
Drain the cauliflower well as follows: place the cauliflower in a clean cloth and squeeze firmly enough to get all the liquid out. If the cauliflower is cooked well enough, the florets will come apart easily, like crumbly dough.
Add crumbled or grated cheese and mix. Squeeze gently with your hands, as you would a dough.
Divide the dough in two (if you want to make 2 smaller pizzas, if not you can use it all for one pizza).
Spread the dough into circles on a baking pan lined with parchment paper. Press gently on the edges to get rid of any small cracks.
Bake for 15-20 minutes at 200 ºC/390 °F in a preheated oven.
Once golden and brown, remove the pizza crust from the oven and add the toppings: tomato sauce, mozzarella, mushrooms and basil.
Bake for another 10 minutes at 200ºC/390°F or until the mozzarella has melted.
Allow to cool for 3-5 minutes before slicing, the slices will still be slightly soft but will harden as they cool.