In a large mixing bowl, stir together the plain flour and ground almonds until evenly distributed. This ensures the almond flour is spread throughout for consistent flavor and texture. Make sure there are no lumps.

Add the cubed, chilled unsalted butter to the flour mixture. Using your fingertips, rub the butter into the flour by lifting the mixture and letting it fall back into the bowl while pressing the butter pieces. Continue until the mixture resembles fine breadcrumbs.

Work quickly to prevent the butter from warming up-cold butter is key to achieving that tender, flaky texture.

Stir in the caster sugar, distributing it evenly throughout the mixture. The sugar should be fully incorporated but don’t overwork the dough at this stage.

Break the medium egg directly into the bowl. Using your fingers or a fork, work the egg into the mixture gradually. The dough will start clumping together. Bring it together with your hands, pressing gently until it forms a cohesive, soft dough. Don’t knead-just bring it together.

Tip the dough onto a lightly floured work surface. Shape it into a smooth ball, then flatten it gently with your fingers into a disc about 2cm thick. This disc shape helps the dough chill evenly and makes rolling easier later.

Wrap the pastry disc tightly in cling film, ensuring no air pockets remain. Refrigerate for at least 3 hours, or ideally overnight. This crucial resting period allows the gluten to relax (preventing shrinkage) and the butter to firm up (ensuring a crisp texture when baked).

When ready to use, remove the pastry from the fridge and let it sit at room temperature for 5-10 minutes to soften slightly. Roll out on a lightly floured surface to your desired thickness (typically 3-4mm) and use according to your tart or pie recipe.