Sift the sugar into a flat bottomed pastry bowl, and work in the soft butter with a wooden spatula until it's fully blended. You can use a k-beater on a Kitchenaid really successfully.

Add the egg yolks and lemon zest, then combine until fully blended. (Again, there's nothing at all wrong with the k-beater).

Add the flour (sifted beforehand) and salt.

Combine again until a compact ball forms. (Yes, k-beater will save your arms and do a good job)

Lift out the dough with your hands and just check it for texture. If it's too sticky, add a little more flour.

Knead the dough, stretching it and regathering it, for a short while (this is called 'fraisage'). Refrigerate for at least 30 minutes before use.

Due to its crumbly consistency, you may need to divide this sweet shortcrust pastry into small balls in order to line a tart tin. Don't fret - patchwork pastry sorts itself out during the baking process.