You can see her recipe in more detail here: Shortcrust pastry You can use the stand mixer with the flat beater to crumble the dough or a food processor.
In a medium bowl, combine the flour, salt and sugar.
Add the cold but not hard butter, cut into small pieces.
Using your fingertips, crumb the mixture until it forms a sand-like consistency.
Work quickly so as not to heat the butter and melt it.
Rub the flour with the butter between your hands to refine the sandy texture. You should obtain a homogeneous mixture resembling coarse sand.
Mix the egg yolk with the water to dilute and pour over the mixture.
Stir with fingertips to combine and form a paste.
Do not knead the dough to try to cohere it together into a ball.
Pour the dough onto the work surface and smearing it with the heel of your hand against a hard surface like a marble counter top. This French technique is called "fraisage"
Push the dough in front of you, bring it back and repeat forward two or three times. Using the French technique "fraisage," the streaks of butter are incorporated into the dough without overworking it. Gather the dough into a ball, smoothing it slightly.
Flatten it into a small disk or square for quick cooling. It will also be easier to roll out.
Wrap it in cling film and refrigerate for at least 1 h before rolling.
The resting time will allow the gluten to relax and the dough will not be elastic when you roll it out.
Take the dough out of the fridge, let it relax a little and roll it out on a lightly floured work surface. You can spread it between 2 sheets of parchment paper to avoid over-flouring.
Roll out to a 3 mm ( 0.12 in ) thickness.
Place the perforated ring in the center to check that you have enough pastry. Leave 3 cm ( 1.18 in ) on each side of the tart ring.
Put the rolled-out dough back in the refrigerator to firm up slightly and prevent it from becoming sticky during lining the tart ring.
Butter the inside of tart ring and place it on a baking sheet lined with parchment paper.
Fold the dough in half and place in the middle of the tart ring, then roll out.
Lower it against the edges of the ring to form a right angle between the bottom and sides. Press it well into the bottom of the ring and up the sides. Pinch the pastry between your thumb and index finger on the sides to make them even and thin. The pastry will be a little higher than the ring.
Trim off any excess with the roller, then trim with a knife to ensure neater edges.
Prick the bottom with a fork and place in the freezer for 30 min.
At the end of this time, prepare the set cream mixture.