Preheat your oven to 400 degrees. Line a rimmed baking sheet with parchment paper or foil for easy cleanup.

Snap the woody ends off the asparagus by bending each spear near the bottom until it breaks at its natural point. Pat the spears dry with a paper towel so the prosciutto sticks and the asparagus roasts rather than steams.

Divide the asparagus into 12 equal bundles of about 5 or 6 spears each. Take one slice of prosciutto and wrap it around the lower third of one bundle, overlapping the prosciutto slightly as you go so it holds the bundle together. The tips and the bottom of the stems can stay exposed. Place the bundle on the prepared baking sheet and repeat with the remaining bundles, arranging them in a single layer with a little space between each one.

Drizzle the olive oil evenly over all the bundles. Season with freshly ground black pepper and a pinch of red pepper flakes if using. There is no need to add salt at this point because the prosciutto is quite salty on its own.

Roast in the preheated oven for 12 to 15 minutes. The asparagus tips should look slightly crisp and the prosciutto should be golden and curled at the edges. Thicker spears may need the full 15 minutes. Check at 12 minutes and press a spear gently with a fork to test tenderness.

Remove the pan from the oven. Immediately scatter the shaved Parmesan over the hot bundles while they are still on the pan. The heat from the asparagus will soften the cheese slightly so it clings. Transfer to a serving platter and add a squeeze of fresh lemon over the top if you like. Serve right away.