I think that leeks are an underused vegetable and too often people only consume them as an ingredient coupled with potatoes in a soup. Although I love a good leek and potato soup or the classic chilled Vichyssoise, I believe that leeks have so much more to offer and a far more adaptable than many people think. With their mild, subtle onion flavour they have a sophisticated taste which is fabulous.
Leeks pair together so well with cheese, eggs, cream and other dairy products and this is a combination that I love to exploit and experiment with! Leek gratins, made with your favourite cheese of choice are particularly good - I especially like to use a mild blue cheese such as Cashel Blue which is delicious. Dishes like these can be used as accompaniments but if served with some crusty bread can form the basis of a meal in their own right.
With the above point in mind, and given leeks’ natural affinity with cheese, eggs and cream, I decided to make a tart that included all these ingredients. This would be a great dish luncheon dish served with a lightly dressed, fresh, leafy-green salad.
Make sure to taste the filling as you go along, seasoning generously, because the tart really does need it and it will make all the difference to the finished dish. I added a generous spoonful of wholegrain mustard at the last moment because I felt that it needed “something else”. I am delighted that I did, because the slight piquancy of the mustard really accentuated the sweetness of the leeks. This is a lovely tart and whilst there are a few steps involved, the labour is worth it.
200g plain flour
100g cold butter, diced
1 egg yolk
1-2 tblsp water
500g leeks, sliced lengthways and then chopped into ½ cm pieces
1 onion cut in half and then sliced
½ tblsp plain flour
150ml double cream
1 large egg
3 large egg yolks
75g Gruyere cheese, grated
1 tblsp wholegrain mustard
1. Place the flour into a large mixing bowl and then tip in the diced butter. Using your fingertips, rub the butter into the flour until the mixture resembles breadcrumbs. Make a well in the centre and add the egg yolk and water. Use a fork to bring the mixture together and form into a ball before wrapping in cling film and chilling in the fridge for at least half an hour.
To make the filling:
2. Heat the butter in a large saucepan. Add the sliced leeks and onions and cook over low heat for about half an hour, stirring regularly. Season to taste. After half an hour or so and once the leeks and onions have softened, but not coloured sprinkle in the flour and stir. Cook for a further 3-4 minutes, stirring continually.
3. Gradually stir in the milk and cream and once the mixture is smooth, cook gently for a further 10 to 15 minutes to cook out the flour. Remove the mixture from the heat and allow to cool. Make sure to season well.
4. When cooled stir in the egg and egg yolks, followed by the cheese and wholegrain mustard.
5. Preheat the oven to 190C/Fan Oven 170C/Gas Mark 5.
6. Roll out the pastry thinly on a lightly floured surface and gently lay 23cm loose bottomed tart tin. Line the pastry with baking parchment and then fill with baking beans. Bake in the oven for 20-25 minutes, removing the parchment and baking beans for the final 5-10 minutes of baking. Remove from the oven and allow to cool slightly.
7. Reduce the oven temperature to 170C/Fan Oven 150C/Gas Mark 3.
8. Pour the filling into the baked tart case and smooth the surface. Bake in the oven for approximately 30 minutes until the tart has set and is a golden colour. Remove from the oven and allow to rest for 15 minutes. Serve at room temperature.