Oven-baking makes the energy and fibre of vegetables available, and caramelises the sugars for tastiness. While the heat can reduce some vitamins, the lack of water maintains others. The addition of oil makes fat-soluble vitamins more available to your body.
Cut your vegetables into large chunks, coat with a small amount of oil and place into a conventional oven on 180°C or fan-forced oven on 160°C and leave for 20–45 minutes—it depends on the size of your cut vegetables.
Remove leafy tops before storing—they pull moisture from the vegetable and impact shelf life.