Preheat oven to 400 degrees and line a baking sheet with parchment.
Break an asparagus to determine where the tough ends begin. Using a sharp knife, slice the remaining asparagus to that same length.
Arrange the asparagus in a single layer on the lined baking sheet and drizzle with olive oil. Season well with salt, pepper and lemon pepper. Add lemon slices on top.
Roast for 20 minutes or until the asparagus is fork tender. Serve immediately.