Make the Crust:

• Preheat oven to 350°F (177°C).

• In a small bowl, mix graham cracker crumbs, sugar, and melted butter.

• Press the mixture firmly into a 10-ounce ramekin.

• Bake for 15 minutes, then set aside to cool.

Make the Filling:

• Increase oven temperature to 400°F (200°C).

• In a saucepan, mix sugar and cornstarch. Slowly whisk in water.

• Cook over medium heat, stirring constantly, until thickened and boiling. Reduce heat.

• Whisk egg yolk in a small bowl. Gradually add a spoonful of hot mixture to temper it.

• Return yolk mixture to saucepan and cook until thick.

• Remove from heat and stir in butter, lemon juice, and zest.

• Pour filling over the baked crust.

Make the Meringue:

• Beat egg white and cream of tartar on medium-high speed until foamy (about 2 minutes).

• Gradually add sugar, ½ tbsp at a time, beating until stiff peaks form.

Top & Bake:

• Spread meringue evenly over filling, sealing the edges.

• Bake for 8-10 minutes, until golden brown.

Cool & Serve:

• Let pie cool to room temperature before refrigerating. Serve chilled.