1-First, prepare the lemon curd filling: Mix 55 grams of caster sugar and 4 grams of cornstarch in a heatproof bowl. Add 1 egg, 45 grams of fresh lemon juice, and lemon peel from about 1/4 lemon, then cook over a bain-marie, stirring continuously until it thickens. Stir in 22 grams of unsalted butter, cover with plastic wrap, and chill for at least 30 minutes. Freeze the curd in 10 equal portions until solid.

2-For the cookie dough, cream together 110 grams of room-temperature unsalted butter, 110 grams of caster sugar, lemon zest from 3/4 lemon, and 1 teaspoon of vanilla paste until smooth.

3-Add 1 egg to the mixture and blend well, then sift and fold in 200 grams of all-purpose flour, a pinch of salt, and 1/2 teaspoon of baking soda to form a soft dough. Chill the dough for at least 20 minutes to make it easier to handle.

4-Use a scoop to portion the dough, flatten each piece, place a frozen lemon curd ball in the center, and fold the dough around it to fully encase the filling.

5-Roll the filled dough into balls and coat each one with granulated white sugar, then place them on a baking tray.

6-Bake in a preheated oven at 180°C (350°F) for 8-9 minutes, until the cookies are soft in the center with lightly golden edges. Let them cool on the tray before serving.