Make the lemon curd

1. Cut the chilled unsalted butter into cubes. Chill in the refrigerator until needed.
2. Add 5 egg yolks, 2 whole eggs, fresh lemon juice, caster sugar and zest of lemon into a heatproof bowl.
3. Whisk the ingredients gently.
4. Place some water in a saucepan, turn on to medium heat. Place the egg mixture on top of the saucepan. Use the double-boiler method to cook the mixture gently and slowly.
5. Keep stirring it until it thickens. It will take around 8 to 10 minutes to finish the process.
6. When the mixture has thickened, remove it from the heat and place the mixing bowl onto a heatproof mat.
7. Add in the chilled butter cubes and mix them well, using a whisk.
8. Sift the mixture once in order to produce a silky smooth lemon curd. Press the lemon curd through the sieve using a silicon spatula.
9. Cover the curd with cling film or store it in a sanitised jar and place in the refrigerator until needed.

Make the sweet crust pastry

1. Add the all purpose flour and sea salt into a mixing bowl. Mix them well and set aside.
2. Place the unsalted butter in a mixing bowl of a stand mixer with a paddle attachment. Beat at medium speed until it is fluffy. Scrape down the sides of the bowl to make sure all the butter is well beaten.
3. Add the sugar and continue to beat well until the mixture becomes fluffy in texture and pale in colour.
4. Turn the speed slightly slower, add the beaten egg slowly into the butter mixture. The mixture might become curdled at this stage, don't be concerned, it's normal.
5. Add in the flour mixture. Mix well at medium low speed until it turns into a dough.
6. Stop the mixer once or twice to scrape down the sides of the bowl to make sure all the flour is well mixed.
7. Once it turns into a dough, stop the mixer.
8. Prepare a sheet of cling film on the work surface. Place the dough in the centre of it and wrap well.
9. Chill the dough for about 30 minutes or until it becomes firm.

Mold the tart shell

1. Preheat the oven to 180°C.
2. Prepare a 9" removable bottom tart tin and slightly grease the bottom and the sides. This step is optional but recommended.
3. Remove the chilled dough from the refrigerator and unwrap it. Place in the middle of the tin.
4. Push and stretch the dough – to the sides of the tin first then gradually push and stretch to cover the bottom of the tin. Try to mould it as evenly as you can.
5. Once you're happy with the tart shell, use a sharp knife or an offset spatula to trim off the rim of the shell to make it look neat and tidy.
6. Use a fork to poke some holes in the dough before blind baking the tart shell.
7. Place the tart on a baking tray before baking it for easy handling.
8. Bake the tart shell in a preheated oven for 20 to 25 minutes or until the edges turn golden brown and the pie crust appears dry.
9. When the pie crust is still warm, lightly brush the surface with the beaten egg white to create a barrier between the filling and the crust.
10. Place the tart shell back in the oven for another 3 to 5 minutes to dry the egg white out.
11. Once it's done, place the tin on a surface until the pie crust cools down completely before unmolding it.

Assemble the tart

1. Make sure the pie crust is completely cooled and the lemon curd is chilled.
2. Scoop the lemon curd into the pie crust as much as you want and level it with an offset spatula. Try to make the top as smoothly as you can.
3. When you're happy with it, chill the whole tart in the refrigerator for about 2 to 3 hours or until the lemon curd is set.
4. Place a tall glass on the work surface and put the tart tin the middle. Gently wiggle the tin the rim of it should come out easily.
5. Use an offset spatula to gently and slowly slice around the bottom of the tart. Once you've gone right, use the spatula to slightly lift up the tart and move it away from the bottom of the tin.
6. Place the tart on a serving plate.

Decorate the tart

1. Place the berries on top of the set lemon curd in any way you like to make the tart look pretty.
2. Dust some icing sugar on top before serving. This step is optional but recommended.