Preheat oven to 210°C/190°C fan.
Mix the raw potatoes, red onion, garlic and courgette in a bowl with the zest of a lemon, the same lemon cut into slices, a tbsp of olive oil and plenty of salt and pepper. Toss well and tip into a lined baking tray.
Place in the oven for 30-40minutes, until the potatoes are cooked through and the garlic soft.
Remove from the oven and add the salmon, cherry tomatoes, black olives, a drizzle more olive oil and a squeeze of lemon. Return to the oven for 10-12 minutes more, until the salmon is cooked.
Squeeze the garlic out of its bulb and toss all of the vegetables in the paste. Taste a spoonful to check the seasoning. Serve with shredded mint and lots of fresh lemon.
TIP Smearing 1tbsp harissa paste to the salmon fillets before adding them to this dish would make for an easy and delicious Middle Eastern twist to this dish.