Rinse asparagus and cut off the woody ends. Place in a single layer on a baking sheet or roasting pan. Drizzle with 1 TB oil, vinegar, and sprinkle with salt and pepper.
Roast 10-12 minutes depending on the thickness of your asparagus.
While the asparagus roasts, heat the remaining 1 TB olive oil in a heavy bottom pan.
Halve the lemons, remove any seeds near the cut, and set lemons cut-side down in the hot pan for 4-5 minutes until they're charred.
Remove asparagus from the pan, and serve immediately with the charred lemons. Squeeze lemon juice over the asparagus, or allow guests to each have their own lemon half to juice.