Pour a little olive oil into a 13x9 inch baking dish and using a pastry brush or your fingers cover the dish.
Place a large pot on a medium heat and add 2 tablespoons of olive oil. When hot, add the onion, garlic and cauliflower and a pinch of salt for seasoning.
1 medium cauliflower, 4 cloves garlic, 1 large yellow onion, 3 tbsp. olive oil, salt
Stir occasionally and continue to cook for about 15 - 20 minutes until tender.
Add 4 cups water and allow to simmer for a further 10 minutes until the garlic, onion and cauliflower are lovely and soft.
Preheat oven to 425°F. 220°C
In a large pan of salted boiling water add the pasta and cook according to the package directions.
1 lb. macaroni
Carefully drain to pan keeping at least 2 cups of the cooking liquid for later.
For safety sake, leave to cool for a few minutes.
Return the vegetables to a large pan and add the cheeses, mustard powder and cayenne and mix thoroughly. Add a little of the cooking liquid to thin it slightly.
2 oz. Parmesan, 4 oz. Cheddar cheese, 1/4 tsp. mustard powder, 1/2 tsp cayenne pepper
In sensible portions, transfer the mixture to a blender and blitz until lovely and smooth.
Add more cooking liquid if required.
The pasta should be cooked by now, drain using a sieve and place in a large mixing bowl or you can reuse the pasta pan.
When the mixture has been pureed, pour onto the cooked pasta and mix thoroughly.
Once combined, transfer the pasta and sauce to the pre oiled baking dish.
In a clean bowl, combine the chopped parsley, breadcrumbs and remining olive oil. season with salt and freshly ground black pepper and mix.
1 1/2 cup breadcrumbs, 1/2 bunch parsley, ground black pepper, salt
Sprinkle the breadcrumb mixture over the pasta and place in the preheated oven for about 15 minutes.
Everything is already cooked so this is to get the breadcrumbs toasty and the sauce thicken. The top should be golden brown ideally.