Rinse the lemons under cool water, slice in half and scoop out the flesh, setting both halves aside.

Squeeze the lemon interiors to extract about ½ cup of lemon juice, straining out seeds or pulp.

In a saucepan, combine heavy cream, sugar, and lemon zest. Heat gently over medium-low for about 5 minutes until sugar dissolves.

Remove from heat and stir in lemon juice and vanilla until slightly thickened.

Strain the mixture into a bowl if desired. Pour into lemon halves, cover with plastic wrap, and refrigerate for 1-2 hours.

Sprinkle a layer of granulated sugar on top of each posset and caramelize with a blowtorch.

Crack the hardened sugar topping with a spoon and serve in lemon halves.