Add the cubed butter and all purpose flour to the bowl of a food processor. Pulse until the butter is broken into the size of peas, about 15 pulses. If you don’t have a food processor, you can also do this with a pastry cutter. 

Slowly stream in the ice water while pulsing the food processor. Add just enough water until the dough comes together in a ball around the blade. 

Shape the dough into a disc and wrap it tightly in plastic. 

Refrigerate for 15 minutes. 

Once the crust has chilled, roll it to 1/4 inch thick on a lightly floured surface. Use your desired cookie cutter to cut out rounds from the dough (I used a 3 inch cookie cutter for my mini-tart pan). 

Lightly spray your pan with nonstick baking spray and place the crusts into the pan. Poke the bottom of the crust a few times with a fork. 

Then, place a a piece of parchment paper over each pie shell and fill it with pie weights (or rice or dried beans). 

Blind bake the pie for 15 minutes. Then, remove the pie weights and parchment paper and bake for another 10 minutes, or until the shells are golden brown. 

Remove the crusts to a wire rack to cool while you make the filling. 

Place a small saucepan over medium heat. Add the egg yolks, granulated sugar, lemon juice, and lemon zest. 

Cook, stirring often, until the mixture has thickened enough to coat the back of a spoon— about 10 minutes. 

Remove from the heat and whisk in the butter. 

Allow the filling to cool completely to room temperature before adding it to the pie shells. 

Place a heatproof bowl over a small pot of simmering water. Make sure the bottom of the bowl isn’t touching the water. 

Add the egg whites and granulated sugar to the bowl and whisk constantly for 5 minutes, or until the sugar has fully dissolved and the temperature of the eggs reaches 165F. 

Then, transfer the mixture to the bowl of a stand mixer fitted with the whisk attachment. 

Beat on medium speed for 4-5 minutes, or until the mixture forms stiff peaks. Add the vanilla and mix to combine. 

To assemble, place 2 tablespoons of filling into the center of each pie shell. Then, top with a dollop of meringue and toast the top lightly with the kitchen torch. Enjoy immediately and store any leftovers in the fridge for up to two days.