Roasting vegetables in the oven caramelizes them and brings out their natural sweetness. This combination of brussels sprouts, green beans, broccoli, carrots, celery, zucchini, onion and mushrooms marries especially well together. I add soy sauce and balsamic vinegar to add another dimension of flavor and get a balance of sweetness, saltiness and acidity.
You can use almost any kind of vegetable combination you want. Sometimes, I add cauliflower, peppers, asparagus, etc. Mix and match to the preference of your taste buds.