Recipe taken from Weber’s Foolproof Favourites Recipe Book.
If you plan to reduce the balsamic vinegar on an indoor cooker, turn on the extraction fan. The simmering vinegar creates a pungent aroma.
- Bring the vinegar to a simmer in a small saucepan over a medium heat, then reduce the heat until a few bubbles are just breaking through the surface. Cook at a slow simmer until about 4 tbsp of vinegar remain. As it nears this amount, the vinegar will cling to the back of a spoon and it will coat the bottom of the saucepan when you rock it back and forth. The total cooking time will be roughly 10 minutes, but keep an eye on the vinegar. If it cooks too quickly or it reduces too much, it will turn bitter rather than sweet. Remove the saucepan from the heat and let it cool to room temperature (the syrup will continue to thicken as it cools).
- Prepare the barbecue for grilling (direct method) over medium heat (180-230°C)
- Remove and discard any tough, woody ends from the asparagus spears. Peel the ends of the asparagus, if liked. Lightly coat the asparagus with the oil and season evenly with the salt and pepper. Lay the asparagus across the bars on the cooking grate. Grill over a medium heat for 4-6 minutes, with the lid closed as much as possible, rolling the spears a couple of times and swapping their positions as needed for even cooking, until lightly charred and crisp-tender.
- Arrange the asparagus on a platter or individual plates. If the syrup is stiff, warm it briefly over medium heat. Drizzle some of the syrup over the spears (you may not need all the syrup). Season with some more salt, if liked. Serve warm or at room temperature.