Preparation Whisk together vinegar, lemon juice, truffle, kosher salt, and pepper to taste. Add oil in a slow stream, whisking. Whisk in broth and season with more salt and pepper if necessary. Arrange asparagus on a steamer rack and sprinkle with kosher salt to taste. Steam asparagus, covered, over boiling water until tender, about 10 minutes for white (4 to 6 for green). Transfer asparagus with tongs to paper towels and pat dry. Divide among 4 plates, then spoon vinaigrette over and serve warm.
Preparation Whisk together vinegar, lemon juice, truffle, kosher salt, and pepper to taste. Add oil in a slow stream, whisking. Whisk in broth and season with more salt and pepper if necessary. Arrange asparagus on a steamer rack and sprinkle with kosher salt to taste. Steam asparagus, covered, over boiling water until tender, about 10 minutes for white (4 to 6 for green). Transfer asparagus with tongs to paper towels and pat dry. Divide among 4 plates, then spoon vinaigrette over and serve warm.