Preheat the oven to 400°F. Trim the bottom 2-inches from the asparagus, and if desired, peel the lower 2 inches of the stalks. Place the asparagus in a baking pan. Don’t worry if the stalks overlap a bit. Drizzle the tablespoon of olive oil over them and toss gently to coat the asparagus evenly. Sprinkle on the salt and pepper, toss again, and spread out in the pan.
Roast the asparagus for 10 to 14 minutes, until just tender and slightly browned. Remember that they will continue to cook a bit after you remove them from the oven, so take them out while they’re still a little firmer than you would like.
Meanwhile, in a small bowl, whisk together the lemon juice, zest, crème fraiche, and Sriracha until smooth. Slowly pour in the ⅓ cup olive oil, whisking all the while until the dressing is thick, then season with salt and pepper.
Let the asparagus cool slightly, and while still warm drizzle over some of the lemon sauce. Serve right away with the rest of the sauce passed on the side if desired.