The first thing on our list is pre-heating your oven to 375ºF. Afterward, grease a 10-inch deep-dish plate or similar equipment that you have readily available. This will make the pie easy to serve.
To make the crust, mix the graham cracker crumbs and chopped walnuts in a bowl. Afterward, pour in the melted butter. Make sure it is not scolding hot! It should be melted but at room temperature.
Once everything is incorporated, press the mixture into your plate. Make sure to cover the bottom and sides!
You can place your crust in the oven for 8 to 12 minutes. When it is done, do not turn the oven off! We still need it. Also, make sure to set the crust aside to cool until it reaches room temperature.
While that is going on, separate your egg yolks from your whites. Make sure no yolk gets into the whites because it will prevent them from rising when we beat the meringue. With a whisk, mix your yolks together with the 2 cans of sweetened condensed milk and the lemon juice. Once everything is well-mixed, pour it into the room-temperature pie crust and place it in the fridge until your meringue is done.
Now onto the meringue! It may seem difficult but it is actually very easy to make. This is because we are just going to cook it in the oven all together so there is no need to pour in hot sugary water or anything like that.
In a metal bowl, place the whites with the cream of tartar and beat them on high. For this purpose, you will want to use a hand mixer or a stand mixer. Whites take a long time to rise if you are whisking them by hand!
Stop once you reach soft peaks. To identify this stage, you need to take the whisk out and see what happens. If the tip of the peak bends over and it kind of collapses a bit, then it is soft peaks. You can also check with a spoon. If you pick some of the mixture and put the spoon upside down, then some of it should fall back into the bowl.
Now add the sugar a bit at a time and continue to beat on high. Keep going until you reach stiff peaks. Check using the tests we described in the previous step: take the beaters out or use a spoon. This time, the peaks you see should be well-defined and the should not move at all.
Also, make sure that all the sugar is dissolved. Grab a bit of the meringue between your fingers to see if there is any grittiness. If so, continue beating until everything is well combined.
Spoon the meringue over the filling. Place it all the way to the edge to seal it. Using the back of the spoon, create texture and peaks that can pick up some color in the oven. This will make your pie look incredible!
Bake it for 10 to 15 minutes. You can also put it in the broiler to give the decorations you made earlier some extra color on top. But keep an eye on it, so that it does not burn!
Let it cool down to room temperature and chill it in the fridge for a few hours before serving it on a hot Summer day!