1 1/2 pounds (680g) asparagus, ends trimmed
1/2 large red onion, thinly sliced
3 tablespoons (45mL) extra virgin olive oil, divided
Fine sea or Himalayan salt
Freshly ground black pepper
1/4 cup (60mL) chopped walnuts
1 small clove garlic, minced
2 tablespoons (30mL) aged dark balsamic vinegar, plus more as needed
4 large roasted red peppers, chopped
1/3 cup (80mL) sliced kalamata olives
1/4 cup (60mL) sliced sundried tomatoes
1 tablespoon (15mL) capers
1/4 cup (60mL) chopped fresh basil

Preheat the oven to 450 degrees F. Toss the asparagus and red onion with 2 tablespoons of the olive oil. Season with salt and pepper. Roast for 6 to 8 minutes, depending on the size, until it just starts to become tender. Remove from the oven and add the walnuts and garlic. Drizzle with 2 tablespoons of the balsamic vinegar, mixing to coat. Roast for an additional 4 minutes, until the walnuts are fragrant and the vinegar is no longer runny. Remove from the oven. Cut the asparagus into bite-sized pieces. Scrape the asparagus, red onion, and walnuts into a large bowl.

Add the roasted red peppers, olives, sundried tomatoes, and capers to the bowl. Mix to combine, adding the remaining olive oil and additional balsamic vinegar, if desired. Stir in the basil. Adjust salt and pepper to taste. Let stand at least 30 minutes before serving.