A great gratin has layers of gorgeously tender vegetables flavoured with herbs, lashings of garlic and either cream or stock to keep everything moist; this recipe is one of my favourites.
2 tablespoons olive oil
knob of butter
3 onions, thinly sliced
¾ cup cream
2 cloves garlic, crushed
1 tablespoon thyme leaves
1 kilogram Agria potatoes, thinly sliced
700 grams crown pumpkin, sliced 1 cm thick
1 kilogram firm but ripe tomatoes, thickly sliced
½ cup freshly grated Parmesan
sea salt and freshly ground pepper
8-10 cherry tomatoes, halved, optional
extra sprigs thyme, optional
24 cm square by 6 cm deep ovenproof baking dish (or similar size)
Preheat the oven to 180°C.
Heat the oil in a large sauté pan and add the butter and onions with a good pinch of salt.
Cover and cook for 10 minutes then uncover and cook until tender and golden, stirring occasionally. Set aside.
Put the cream, garlic and thyme in a saucepan and bring to just below the boil.
To assemble: Spread half the onions in the base of the baking dish and layer up half each of everything in the following order, seasoning each lightly: potatoes, pumpkin, tomatoes, cream and Parmesan. Repeat to make another layer. Cover the vegetables with a piece of baking paper then cover tightly with foil. The tomatoes will react with the foil if in direct contact.
Bake for about 1 hour until tender then uncover and if using, top with the cherry tomatoes and extra thyme. Bake for 20 minutes or until the juices are reduced and thickened and the top is a lovely golden colour.