In a food processor, pulse together the flour, icing sugar, and salt. Add the cold butter cubes and pulse until the mixture looks like fine crumbs.

Whisk the egg separately, then slowly pulse it into the flour mixture until a soft dough forms. Don’t overmix — stop as soon as it comes together.

Place the dough between two sheets of parchment paper and roll it out to about ⅙ inch (4 mm) thick. Chill flat in the refrigerator for at least 1 hour (or up to 24 hours).

Cut out circles slightly larger than your muffin tin openings. Gently press each round into the muffin pan, making sure the corners are snug to prevent shrinking. Chill again for at least 2 hours (overnight is even better for bakery-style results).

Preheat oven to 325°F (160°C). Prick the bottoms with a fork. Line each shell with crumpled parchment and fill with baking beans or rice.

Bake for 15 minutes, remove the weights, then bake another 15 minutes until golden and dry. Let cool completely.

In a small saucepan, whisk together egg yolks, sugar, and lemon juice. Cook over very low heat, whisking constantly, for 3–5 minutes until it begins to thicken.

Add butter a few cubes at a time, whisking until fully melted before adding more. Stir in the lemon zest.

Continue cooking on low, whisking constantly, for 5–15 minutes until thick and silky. It’s ready when it coats the back of a spoon and a line drawn through it stays clean.

While still warm, pour the lemon curd into the cooled tartlet shells. Tap gently on the counter to release air bubbles.

Refrigerate the Lemon Curd Tartlets for at least 2–3 hours until set and beautifully glossy.

Serve chilled for that perfect creamy-meets-crisp bite.