Preheat the oven to 160°C / 320°F. Line a baking sheet with parchment paper, lightly greased and floured.

Separate the egg: beat the white to soft peaks in a clean, dry bowl. In another bowl, whisk the yolk and sugar until pale and creamy. Fold in the flour gently (do not overmix), then incorporate the beaten egg white with delicate movements.

Spread the batter over the prepared sheet and bake for about 5 minutes, until lightly golden. Let it cool for a few minutes, then cut out small circles using a cookie cutter or the rim of a glass. Set aside.

Place the milk in a small saucepan. Heat until just before boiling, then remove from the heat. Add the jasmine blossoms and lemon zest. Cover and steep for 10 minutes.

In a bowl, whisk the egg yolks and cornstarch until smooth (add a splash of milk if needed). Strain the infused milk to remove the blossoms and zest, then pour it slowly into the yolk mixture, whisking constantly. Return the mixture to the saucepan, add the sugar, and cook over medium heat, stirring constantly until it thickens and just begins to bubble. Remove from heat.

In individual ramekins or glasses, place a biscuit circle at the bottom. Pour in the jasmine custard and top with another biscuit. Let cool at room temperature, then refrigerate for at least 2 hours.

Garnish with lemon zest and a fresh jasmine blossom for a quiet, perfumed finish.