Preheat the oven to 425F/220 C.
Place all the vegetables onto 2 or 3 (*****) foil-lined roasting pans/baking sheets.
Generously drizzle with oil. Season well with salt & pepper. Add mustard, garlic, balsamic vinegar, sugar & rosemary.
Massage all the veggies with your hands to coat. Roast on the middle and top rack of the oven for about 1 hour shaking the pan every 20 minutes. Roast until veggies are nicely browned.
SERVES 10-12
*****Never overcrowd the veggies. They must only be one layer think otherwise they will stew & not brown and caramelize. You may need to divide them into 3 or 4 batches depending on how much you are making.