Preheat the oven to 450 ℉ (230 ° C) and place the rack in the upper third.
Combine all the dressing ingredients and set aside.
In a saucepan, bring the water and salt to a boil, reduce the heat and cook the oats, covered, for 1 hour. Occasionally check if the water level is sufficient and add more if necessary. The oats are cooked when the grains are tender but still a little al dente. Drain the oats and set aside.
While the oats cook, line a baking sheet with parchment paper and distribute the vegetables and herbs. Drizzle the vegetables with half the vinaigrette. Coat the vegetables well with your hands, turning them over on the baking sheet.
Cook the vegetables for 30 to 40 minutes, turning them every 15 minutes, until they are nicely browned and caramelized. Discard the herbs.
Transfer the vegetables to a serving dish, top with the oats and drizzle with the remaining dressing. Serve hot or warm.
The little extra
This dressing is delicious with other grilled vegetables such as broccoli, asparagus, winter squash, Brussels sprouts…