Wash the lemons well and dry them completely. Finely grate the yellow skin without reaching the bitter white part. Then squeeze fresh lemon juice and strain it to remove seeds and pulp.

Pour the heavy cream into a medium saucepan. Add sugar, lemon zest, and a small pinch of salt. Place the pan over medium heat and stir gently until the sugar dissolves.

Continue heating the cream until it reaches a gentle boil. Stir often so the cream does not scorch. Let it bubble gently for about three minutes while keeping the heat steady.

Remove the saucepan from the heat. Slowly add the fresh lemon juice while stirring continuously. The mixture will begin thickening naturally as the acidic lemon juice reacts with the warm cream.

Stir in the vanilla extract until evenly mixed. Taste carefully after the mixture cools slightly. Add a little extra lemon juice if you prefer a brighter and sharper flavor.

Place a fine-mesh strainer over a clean bowl. Carefully pour the warm mixture through it. This removes the lemon zest and creates an especially smooth texture for your finished dessert.

Divide the warm lemon mixture between six small glasses. Avoid filling them completely to the top. Small dessert glasses work beautifully because this dessert is rich and creamy.

Let the filled glasses cool at room temperature for a short time. Cover them gently and refrigerate for at least three hours. The mixture will become thick, silky, and spoonable as it chills.

Remove the possets from the refrigerator just before serving. Add fresh berries or a small lemon slice. Serve cold and enjoy the creamy texture with the bright citrus flavor.