- 1 red onion
- 2 garlic cloves
- 400g chopped tomatoes
- 3 courgettes
- 50g breadcrumbs
- 125g mozzarella
- 50g rocket
- A handful of oregano, leaves only
- 2 tbsp balsamic vinegar
- 1½ tbsp olive oil
- Sea salt
- Freshly ground pepper
- 1.
Heat your oven to 180°C/Fan 160°C/ Gas 4. Peel and finely chop the onion. Peel and grate the garlic cloves.
- 2.
Set a frying pan over a medium heat for a few mins. When warm, drizzle in 1 tbsp olive oil and add the onion. Season. Gently cook for 5 mins till softened. Stir in the garlic and cook for 1 min more. Pour in the tin of chopped tomatoes and add 1 tbsp balsamic vinegar (keep the rest for later). Pop a lid on the pan and simmer for 15 mins, stirring now and then.
- 3.
While the tomato sauce is cooking, slice the courgettes into thin strips lengthways. You should get 6-8 slices per courgette.
- 4.
Heat a dry frying or griddle pan till smoking hot. Lay some courgette slices in the pan (no need for oil). Cook for 2 mins on each side. They should be slightly charred and softened. Place on a plate. Repeat with the remaining courgettes.
- 5.
Tear the mozzarella ball into small pieces. Pick the oregano leaves off their stalks.
- 6.
Taste and season the tomato sauce. Spoon ¼ of the tomato sauce into a small or medium baking dish. Lay some courgette slices on top to cover the sauce. Scatter ¼ of the mozzarella over the courgette. Sprinkle over some oregano leaves.
- 7.
Keep repeating the layers, finishing with a scattering of mozzarella (keep any leftover oregano for garnishing later). Scatter over the breadcrumbs and finish with a good crack of black pepper. Slide into the oven for 30 mins till the top is golden and the mozzarella has melted.
- 8.
While the gratin is cooking, whisk the remaining balsamic with ½ tbsp olive oil and some seasoning.
- 9.
Remove the gratin from the oven. Leave to rest for a couple of mins. Meanwhile, toss the rocket with the balsamic dressing. Scatter the remaining oregano leaves over the gratin and serve it with the rocket salad.