"'Real men eat quiche', is what the team told me as I made this. I don't know about that, but I can tell you that Wensleydale cheese is a great addition," says Martin.

Ingredients

(Serves 8)

1tbsp olive oil

15g butter

2 red onions, sliced

Sea salt and freshly ground black pepper

2 eggs

2 egg yolks

300ml double cream

100ml full-fat milk

2 small courgettes, around 225g, thinly sliced, lengthways

3 courgette flowers, sliced lengthways

175g crumbled Wensleydale cheese

For the pastry:

300g plain flour, plus a little extra for dusting

150g butter, chilled and diced

A pinch of sea salt

A few thyme sprigs, leaves picked (optional)

1 egg, beaten

Method

1. Start by caramelising the onions for the filling. Heat the oil and butter in a medium pan over a medium heat. Once the butter has melted, stir in the onions and a pinch of salt. Cover and cook over a low heat for 20-25 minutes, stirring every now and then until the onions have softened and caramelised. If they look as though they're burning, add a tablespoon of water and stir in . Spread onto a plate and set aside to cool.

2. Make the pastry. Put the flour into a bowl, add the butter, salt and thyme (if using) and rub together with your fingertips until the mixture resembles coarse breadcrumbs. Add the egg and mix with a knife until the mixture forms clumps, then bring together lightly with your hands. Add a couple of teaspoons of water if the dough feels dry. Dust a clean work surface with flour and knead lightly and quickly until smooth. Wrap in clingfilm and chill for 30 minutes. Preheat the oven to 180°C (160°C fan)/350F/gas 4.

3. Lightly flour your work surface and roll out the pastry to a rough circle measuring about 32cm in diameter. Carefully lift the pastry into a 27cm fluted tart tin and gently press into the corners.

4. To make the filling, put the eggs and egg yolks, cream and milk into a jug and whisk together. Season well and whisk again. Spread the onions over the base of the pastry, arrange the courgettes and courgette flowers on top and scatter over the cheese.

5. Pour the egg mixture into the tart tin and give it a little shake so that it spreads evenly. Carefully slide the tart tin onto a baking sheet and bake in the preheated oven for 45-50 minutes, until the filling is set.

6. Once cooked, take the quiche out of the oven, let it sit for about five minutes, then trim the pastry edges. Serve hot, warm or cold with a green salad. Leftovers keep very well for the next day but the filling will be a little firmer after a night in the fridge.

James Martin's Great British Adventure: A Celebration Of Great British Food With 80 Fabulous Recipes by James Martin is published by Quadrille