Using a double broiler, mix all ingredients except the vanilla in alarge heat safe bowl.
Pour the mixed ingredients into the bowl of a standing mixer.
Place the bowl over the prepared double broiler.
Start to simmer the water and heat the mixture until the candy thermometer reaches 165 ℉ and all the sugar has dissolved, about 5-10 minutes from when the water starts to simmer.
While heating, gently mix to ensure even cooking.
Once all the sugar has dissolved and the mix is 165 ℉, remove from heat and place the bowl in a standing mixture and mix on medium highfor 5-7 minutes until the egg whites stiffen up and the mixture starts to cool.
Once it starts to stiffen up, add the vanilla.
Scoop the marshmallow frosting into the disposable piping bag.
Spoon on 2 tbsp of lemon curd onto the top of the cupcake.
Pipe the marshmallow meringue onto the top of the lemon curd.
Using a kitchen torch, toast the marshmallow frosting