This is the perfect tart for autumn, with its sweet-smoky flavours and comforting pastry it makes for the perfect lunch or simple supper with a good salad.

Serves 6

For the pastry

250g flour

175g butter, cold and cut into small pieces

2 egg yolks, lightly beaten

Beans for baking blind

For the filling

50g butter

2 Tbsp olive oil

400g onions, finely sliced (a mandolin works well)

120ml cream

2 eggs

¼ tsp freshly grated nutmeg

Sea salt

Freshly ground pepper

Method

To make the pastry, put the flour in a bowl, add the butter and rub together with your fingertips until the mixture resembles breadcrumbs.  Using a bread and butter knife in a cutting motion, combine the egg yolks with the mix until the pastry comes together, if it is a little crumbly add one teaspoon of cold water at a time until you get a firm, yet moist dough.   Turn out onto a lightly floured bench and quickly knead until the pastry is even and smooth, then wrap and place in the fridge to chill for at least 30 minutes.

While the pastry is resting make the filling.  Melt the butter with the oil in a large-heavy based pot or fry pan.  Add the finely sliced onion and cook over a low heat for 30 minutes.  Cooking the onions long and slow is essential as the natural sweetness comes out of them and the texture becomes soft and they almost melt together. Cool slightly.

Heat the oven to 200C

Roll out the pastry on a lightly floured surface and line a 30cm push up bottom flan tin or something similar, making sure there are no cracks.  Return to the fridge and rest for another 30 minutes, then line with baking paper and fill with baking beans.  Bake for 20 minutes, reduce the heat to 160C and cook for a further 15 minutes, or until the pastry is golden and set.

Add the onion mixture and spread evenly over base.  Carefully pour over the egg mix and grate heavily with nutmeg.

Bake for 20-30 minutes or until the edges are set but the centres is still slightly wobbly>

Cool slightly and cut into desired portions and enjoy either on its own or with a crisp green salad,