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.