Cut the chorizo into slices and the slices in quarters. Fry this in a frying pan (don't add any fat) and leave to drain on a piece of kitchen paper. It releases enormous amount of fat.
Grate the cheeses together and cook the pasta according to the instructions on the package and leave to drain.
Chop the cauliflower finely and bake in a pan for a bit just so it is not entirely raw going in. It will cook in the oven.
Grease an ovendish with some butter and make a layer of the cooked pasta. Add the cauliflower on top and the chopped chorizo. Make another layer of pasta
Now you make the cheese sauce. Melt 50 gram of butter in a saucepan and add the flour and stir until it combines. Leave this to cook for a bit before you add the cream and/or milk. You can use only cream or only milk or a mix of both. Add a little bit at the time and stir out all lumps and bumps before adding some more. I like to use a whisk to do this. What you will be left with is a sauce that is thick but not too thick. A little bit like a regular pouring sauce.
Add the cheese in and stir it all through. Add pepper and salt if needed (depending on the saltiness of your cheese) and pour the sauce over your pasta.
Finish off with a bit of grated cheese on top and put into the oven for about 30 minutes or until golden.