Roast all the veg together and top with grated cheese then melt under the grill. Serve with sour cream on the side.
Or cook all the veg, frying the onion and garlic, make a cheese sauce, put all the veg in a dish, cover with the cheese sauce, put under the grill to brown, and serve (like cauliflower cheese) with plain rice.
Chop the spuds into wedge shapes and roast in oil with some paprika, then make a salsa by cooking down the diced carrots, toms, garlic, onion and a good wodge of chilli and/or cayenne. And maybe Lea & Perrins, because it makes everything better! Lob over the spuds with grated cheese for 2 mins at the end of cooking. Serve the sour cream at the end.