1. Bring a large pot of water to a boil. Blanch asparagus for 1 minute. Drain and cool under cold running water.

2. In a large salad bowl, toss together red leaf, romaine, frise asparagus, and black olives.

3. In a medium bowl, whisk together vinegar, salt and pepper, and sour cream. Slowly whisk in the olive oil until completely combined. Pour vinaigrette over the salad, toss to coat, and serve immediately.