Chop the cauliflower into chunks, then place in a large pan, cover with water, place the lid on the pan and bring to the boil. Once boiling cook for about 5-8 minutes, or until soft. Drain in a colander.
Meanwhile, season the pork with salt and pepper.
Heat a non-stick pan on a high heat, place 1 tablespoon of olive oil in the pan, add the pork fillet and sear for about 4-6 minutes, turning regularly so it sears and browns evenly on all sides. Set the pork aside on a plate.
Toss the sage leaves in the pan fat for 5-10 seconds or so, stirring continuously, then set aside on a plate.
Mash the cauliflower by adding it back to the pan, add half the cheese, add 1 tablespoon of butter and mash well until you reach a relatively smooth consistency. Season with salt and pepper to taste.
Spread the cauliflower out to the edges of a casserole dish (about 10.5 x 6.5 inch dish/26.5 x 16.5 cm), then sprinkle over the remaining cheese.
Sit the pork on top of the cauliflower, pushing it down slightly to embed in the cauliflower.
Place under a preheated broiler/grill for 10-12 minutes.
Remove, then lay out the prosciutto around the pork in waves, sprinkle over the crispy sage crumbling it over the pork and cauliflower, then broil/grill for 2 more minutes, or until the pork is cooked to your liking.
Rest for 2 minutes, then slice the pork and dish up – delish!
Optional, serve with a side of greens such as lightly sautéed spinach.
*Can be stored in the fridge and reheated. Reheat in the microwave, or cover the casserole dish with foil and reheat in a preheated 400F/200C oven for about 15 minutes.