Line tin with baking cups (jumbo or cupcake sized muffin tin, or in 4-inch tart pans)
Place the graham crackers in a plastic zip-lock bag. Seal the bag and crush the crackers.
Pour into a bowl. Add the brown sugar, butter and vanilla paste and mix well.
Press even amounts into the bottom of the baking cups.
Using a flat bottom cup or glass a little smaller the the bottom of the cups, press firmly and even-out the lip that forms. You will have a crust with a dip in the center for the filling and sides that form the lip.
Bake for 5 - 6 minutes, until the crust sets. Let cool completely.
Carefully peel off baking cups from cooled tartlet shells. Set the crusts on a baking sheet.
For the Filling
Crack whole egg and yolks into a medium-small size mixing bowl. Set aside.
In a saucepan, combine sugar, flour, cornstarch, and salt. Add water, lemon extract, and lemon zest. Mix.
Cook over medium-low heat, stirring constantly, until mixture boils.
Beat 1/2 cup of the mixture into the bowl with the whole egg and yolks; return to saucepan.
Simmer 3 minutes, then stir in butter until melted.
Pour or spoon into tart let shells; cool one hour.
For the Meringue
Beat egg whites on medium-high speed in the bowl of your stand mixer with the whisk attachment until frothy, about 1 minute.
With motor running, gradually add 1/2 cup sugar. Beat until stiff peaks form, 5-7 minutes. Mix in lime zest and lime juice.
Top the tartlet's with the meringue. It's important that the meringue be sealed to the edges of the crust, otherwise the proteins in the egg whites will start to shrink in the oven's heat.
