Preheat the oven to 350 degrees.

Place graham crackers in a food processor and pulse to crush into fine crumbs. Alternatively, place graham crackers in a zip top bag and crush using a rolling pin or can until fine crumbs remain.

To the bowl of the food processor (or add crumbs to a bowl if crushing them in a bag), add brown sugar and melted butter and pulse until combined and the butter is coating all the crumbs.

Press graham cracker crumbs, using the bottom of a cup, tightly into the bottom and sides of a 9 inch round tart pan.

Bake the crust for 8-10 minutes until it starts to turn golden brown. Remove from the oven and set aside to cool.

Whisk everything but the butter together in a small saucepan.

Turn the heat to medium-low, add the butter and stir continuously until the curd begins to thicken and reaches 170 degrees on an instant-read thermometer, about 6 minutes. Don’t worry if you see some curdled eggs in the curd as you will strain the curd next.

Strain the curd into a bowl using a fine-mesh strainer and discard any solids.

Once the crust is cool, pour the curd into the tart pan and smooth the top. Refrigerate until ready to serve, at least 2 hours. Top with the meringue prior to serving.

In a medium bowl set over a pan of about 2 inches of gently boiling water that is not touching the bowl, add egg white and sugar.

Constantly whisk the sugar and egg whites for about 4-5 minutes until the sugar has dissolved completely or an instant read thermometer reads 160 degrees.

Remove the bowl and place into a stand mixer or use a hand mixer and mix on low speed gradually increasing to medium high speed for 5 minutes (longer if using a hand mixer) until the meringue is thick and glossy.