Place the asparagus and shallots in a large bowl, and pour the olive oil and 2 tablespoons (30ml) of the vinegar over. Season with salt and pepper and toss to coat evenly. Spread the asparagus out in a single layer on a baking tray.
Roast for 20 minutes or until tender and bright green. Shake the tray about half way through to roll the spears over so they cook evenly. Remove from the oven and drizzle the remaining vinegar over the asparagus. Toss lightly to coat, and serve immediately.