Making Heston Blumenthal's Lemon Tart

It is very good advice that, when you have guests arriving, it is never a great idea to make an untried recipe. Racking my brain for dessert ideas the other day, a fit of bravery took over and I Googled up the Lemon Tart recipe I had seen a few nights earlier on Heston Blumenthal's How to Cook Like Heston (TV One, 8pm Saturdays, if you're a New Zealand watcher). It's a safe assumption that if Heston has published it then he has probably trialled the recipe about 25 times, so I through caution to the wind, told myself I too could cook like Heston and hit the print button.

We had a lovely dinner with our friends and Little Miss nearly 5 was overjoyed to see her buddy. After rather a lot of faffing around the Lemon Tart was excellent. Having spent many years telling students to always thoroughly read the recipe before beginning, I failed to take my own advice only to discover that Heston expects the pastry chilled for an hour: good thing The Man of the House was picking Little Miss up from Preschool.

Heston Blumenthal's Lemon Tart 

Slightly tweaked by me - sorry Heston. It serves 12 people, takes ages to make, but is thoroughly worth it!

Pastry
300g (2 cups) plain flour
150g butter
120g icing sugar
3 large egg yolks
1/2 vanilla bean, seeds scraped
1/2 lemon, zest finely grated
1 egg white

Filling
5 lemons, zest finely grated and juiced
300ml cream
390g caster sugar
9 large eggs
1 large egg yolk

To make the pastry, using a food processor, mix the flour, butter and salt until it becomes a sand-like texture.

In a tall container blitz together the icing sugar and egg yolks with a stick blender.

Add the vanilla seeds and lemon zest to the egg yolk mixture, and then add to the bowl of the food processor and continue to mix until fully combined and a very soft dough has formed.

Mould the dough into a flat rectangle and wrap it in plastic wrap before placing in the fridge. Heston said 'at least 1 hour', my schedules gave me 20 minutes. 

Preheat the oven to 190 deg. C. 

Roll the dough between a sheet of baking paper and a sheet of plastic food wrap until it is quite thin. 

The recipe asked to freeze the sheet for 30 minutes: I didn't have that time either, and the average domestic freezer wont fit a pastry sheet, so I just boxed on and removed the baking paper from the pastry, then used the plastic wrap to stabilise the pastry while I put it in the 26cm loose bottomed tart tin. 

Making sure to press it into the edges and leave the pastry hanging over the edge.

Take a sheet of baking paper and scrunch it up several times to eliminate any sharp edges. Prick the dough with a fork all over the surface. 

Place the baking paper on top and add enough coins (or baking beans) to fill the casing one-quarter of the way up. Place in the preheated oven to bake for approximately 20 minutes or until fully cooked. 

LM 4 was quite distressed about me using the contents of her money box to cook the pie.

After 20 minutes, remove the baking paper and coins and, using a pastry brush, brush the entire surface of the pastry case with the egg white. This  will ensure that the pastry is sealed. Return the pastry case to the oven for an additional 10 minutes.

Remove the pastry case from the oven and allow to cool a little before adding the lemon filling. Turn the oven down to 120deg. C.

While the pastry shell is baking make the filling: 

Place all the filling ingredients into a heatproof bowl and mix together using a spatula. 

Set the bowl over a saucepan of simmering water and allow to warm up until the temperature reaches 60ºC. 

At this point, strain the mixture through a fine sieve into a jug. 

With a spoon, remove the bubbles from the surface of the liquid.

Slide the oven rack out a bit, put the warm pastry case inside the oven. Fill the case to the top, slide the rack carefully back in, and bake the tart for approximately 25 minutes or until the temperature of the filling reaches 70ºC. 

I had some filling left over so I just popped it into a couple of ramekins and made mini desserts.

Allow to cool completely at room temperature.

Before serving, trim the overhanging pastry by running a sharp knife round the top of the tart tin and discard the left over pastry. Place the dish on top of an upturned mug and remove the sides of the tin by gently pushing them down. Place the tart, base and all on a large, flat serving plate.

All this might sound like too much trouble, but it is indeed well worth it. Make it once and it wont seem so difficult. We served ours with whipped cream and apricots roasted with brown sugar.