Begin by rinsing and drying 1 to 1½ fresh lemons. Slice each lemon in half and scoop out the flesh, reserving the shells for serving.

Squeeze the reserved lemon flesh into a measuring cup until you have about a half cup of fresh lemon juice, straining to remove seeds and pulp.

In a saucepan, combine 2 cups of heavy cream, ½ cup of granulated sugar, and the zest of the prepared lemons. Heat over medium-low for about 5 minutes, until the sugar dissolves.

Remove the saucepan from heat and stir in the reserved lemon juice and 1 teaspoon of vanilla extract. Allow the mixture to cool for a few minutes before pouring into lemon halves.

Carefully pour the cream mixture into the lemon shells, filling nearly to the top. Refrigerate for 1 to 2 hours to allow the posset to set.

Just before serving, sprinkle a thin layer of granulated sugar over each set cream and use a blowtorch to caramelize the sugar until golden-brown.