Begin by preheating your oven to 375°F and positioning the oven rack in the center. In a medium-sized bowl, combine the graham cracker crumbs and sugar. Pour in the melted butter and mix until everything is moistened and cohesive. Start with a fork to incorporate, then use your hands to ensure an even mixture.

Transfer the crumb mixture into a 9-inch pie pan with a 1.5-inch depth. Use your fingers and the base of a flat-bottomed glass or measuring cup to firmly press the crumbs into the bottom and along the sides of the pan, aiming for about a ¼-inch thickness.

Place the pie crust in the oven and bake for approximately 10 minutes, or until it takes on a light golden hue. Once done, remove the crust and place it on a wire rack to cool slightly. Adjust the oven temperature to 325°F for the next step.

In a clean medium bowl, whisk together the egg yolks, sweetened condensed milk, fresh lemon juice, and finely grated lemon zest. Stir until smooth and fully combined. Pour the creamy lemon mixture into the still-warm pie crust, spreading it evenly with a spatula.

To prepare the meringue, bring a small saucepan with about ½ inch of water to a gentle simmer over low heat. Select a heatproof bowl (ideally the bowl of a stand mixer) that fits snugly over the pot without the bottom touching the water. Place the egg whites and sugar in the bowl and whisk continuously until frothy and smooth.

Continue whisking over the simmering water until the mixture reaches 115°F (or feels very warm to the touch). This process should take around 2 to 4 minutes. The sugar should be completely dissolved, leaving no gritty texture.

Remove the bowl from the heat and attach it to your stand mixer fitted with a whisk attachment. Add the cream of tartar and beat the egg whites on medium-high speed until thick, glossy peaks form. The meringue should hold its shape but have soft curls at the tips, which typically takes 3 to 5 minutes.

Carefully spoon the meringue onto the lemon filling, starting from the center and working outwards. Spread it gently with the back of a spoon, ensuring the meringue touches the crust’s edge to create a seal and prevent shrinking. Use the spoon to create decorative swirls and peaks on the surface.

Place the pie in the oven (at 325°F) and bake for about 20 minutes, or until the meringue has a light golden-brown color. Remove the pie from the oven and let it cool completely on a wire rack for at least 3 hours. This cooling period allows the filling to set and the pie to reach the perfect serving consistency.

Slice and serve this classic lemon meringue pie at room temperature. Enjoy the balance of tart lemon filling, crunchy graham cracker crust, and airy, lightly toasted meringue topping!