Preheat the oven to 180°C.
Bring a large saucepan of salted water to the boil and cook the potatoes until tender; usually 15-20 minutes. Drain and allow to steam and cool to one side.
Heat the olive oil in a large frying pan set over a medium heat. Fry the sausages until golden all over, turning occasionally. Add the onions and garlic and cook until the onions are soft, stirring occasionally.
Bring a large saucepan of salted water to the boil and parboil the broccoli for 3-4 minutes. Drain and refresh in iced water.
Cut the potatoes in half and arrange in the base of a ceramic roasting tin. Dot the butter on top and arrange the sausages and broccoli evenly on top. Bake for 5-7 minutes until hot. Remove and season.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.