Preheat oven to 180°C (350°F).

Place sausages on a lightly greased baking sheet. Bake for about 10 minutes.

Mix together potatoes and Brussel sprouts with the olive oil, salt, pepper, and sprigs of thyme if using. 

Place vegetables on baking sheet and continue cooking for 15 minutes.

Add potatoes and bake another 10 minutes or until sausages are cooked with an internal temperature of 71°C (160°F). Serve.