For this dish, I like thick-stemmed green asparagus and thinner-stemmed white spears (which become more bitter as they thicken). How long it takes to roast your asparagus will depend on how thick the stems are. You can also use only green asparagus if you wish.
2 pounds (1 kilogram) white and green asparagus, tough ends removed, peeled if desired
2 tablespoons olive oil
Salt to taste
1/2 cup mayonnaise
1/4 cup chopped chives
1 cup chopped arugula
2 tablespoons lemon juice
2 teaspoons capers
1 teaspoon Dijon mustard
Freshly ground black pepper
Preheat oven to 450 F.
Toss asparagus with olive oil and season with salt. Lay asparagus in a single layer on a cookie sheet and roast for 5 to 10 minutes (depending on thickness) or until asparagus are browned and crisp-tender. Set aside.
Combine mayonnaise, chives, arugula, lemon juice, capers and mustard in a food processor and process until smooth. Season with salt and pepper to taste.
Place asparagus in a serving dish and spoon over sauce.