In a medium bowl, whisk together yogurt, garlic powder, onion powder, pepper and salt. Slowly pour in buttermilk, whisking constantly. Mix in chives.
For best results, make dressing ahead of time and let sit in refrigerator overnight.
Preheat oven to 400 degrees F
Wash and break ends off of asparagus. On a baking sheet with a lip (like a jelly roll pan), place asparagus and drizzle with olive oil. Sprinkle with salt and pepper; toss until fully coated. Cook for 10-12 minutes (depending on size of stalks.) Let cool 5-10 minutes before serving.
For each serving, divide asparagus into six shallow bowls and pour 1/3 cup dressing on top. (Note: there may seem to be a lot of dressing, but asparagus will absorb some of the liquid.)