Preheat the oven to 200 degrees Celsius/ 400 degrees Fahrenheit. Line a baking tray with baking paper.
Clean the asparagus. Dry the spears and remove the tougher woody ends. Lightly coat the asparagus spears with olive oil. Form the bundles by wrapping about 4-6 asparagus spears (depending on their thickness) in one or two bacon slices (depending on their size as well). Place the asparagus bundles on the prepared baking tray and sprinkle with some freshly ground black pepper.
Roast in the oven for about 12 minutes. If the asparagus spears are very thin, start checking after 10 minutes or so, if the asparagus spears are thicker, they might need about one or two extra minutes. Check by piercing with a fork, they should be softer, but still have a bite. Serve immediately.
German bacon is very thin and narrow, so I used 2 slices for each bundle. If your bacon is wider, one slice should be enough.