Boil or steam the carrots until tender and drain them, but holding back 400ml of the water but discard the rest.
Now in a blender, blitz the carrots, water and milk until smooth and pour in to the slow cooker.
Stir in the macaroni along with the cheese, place the lid on top and cook on low for 2 hours without taking the lid off. If using an oven, my friends over at Slow Cooker Saddos say try preheating your oven on 80 degrees and place in a lidded casserole for 2 hours.
Once cooked, give everything a stir (and not beforehand), season again if needed and serve.