Heat oven to 220C/200C fan/gas 7.
Place the onion, courgettes and red
pepper in a baking dish, large enough
to fit them in a single layer. Drizzle over
2 tbsp of the olive oil and season. Cook in
the oven for 20 mins.
Meanwhile, heat the remaining olive
oil in a frying pan and cook the sausages
for about 5 mins until lightly browned
on all sides.
Stir the garlic and chopped tomatoes
into the veg, season again, then place the
sausages on top and return to the oven
to cook for a further 20 mins until the
vegetables are tender.