Chop the dark chocolate and place it in a microwave-safe bowl. Microwave for 30 seconds, then stir and continue in 15-second intervals until fully melted.
Line a tray with baking paper and keep it nearby.
Dip each strawberry into the melted chocolate, place it on the tray, and immediately sprinkle with chopped hazelnuts before the chocolate sets.
Repeat with the remaining strawberries.
Transfer the tray to the freezer for 10 minutes to allow the chocolate to set.