Whip together the butter, lime juice and coriander in a small bowl until well combined. Transfer the butter mixture onto a large piece of plastic wrap. Gently wrap and form the butter into a log. Freeze until ready to use.
Prepare a barbecue for medium-high heat.
Mix together the steak seasoning and chilli powder in a small bowl. Rub the seasoning blend onto both sides of the venison steaks.
Barbecue the steaks until cooked; 5 to 8 minutes per side for medium.
Top each steak with a slice of the lemon-coriander butter to serve.