For the graham cracker crust, grease a 9-inch pie pan very lightly with non-stick baking spray (or rub it with softened butter). Wipe out any excess grease with a paper towel. 

In a large bowl, mix together the graham cracker crumbs, granulated sugar, and melted butter. Mix just until it resembles wet sand. 

Press the crust firmly into the bottom and sides of your prepared pie pan — the tighter you pack the crust, the less crumbly it will be! Freeze the crust for 1 hour. 

While the graham cracker crust sets in the freezer, prepare the lemon pudding. Whisk the pudding mix and whole milk in a large microwave-safe bowl. Microwave the pudding for 8 minutes, stirring every 2 minutes. 

After 8 minutes the pudding should be thick and bubbling — if it isn’t thick enough to coat the back of a spoon, cook it for an additional 2 minutes. 

Whisk in the lemon juice, lemon zest, and vanilla extract. Place a piece of cling wrap directly touching the surface of the pudding and place it into the fridge until the crust is finishing setting. 

Once the crust and pudding are chilled, pour the pudding carefully into the crust and spread it out to create an even layer. Place the pie back into the fridge to set for 3 hours (or until the pudding is fully set). 

When you’re about ready to serve the pie, it’s time to make the meringue. Heat a small saucepan of water over medium heat and bring the water to a simmer. Place a heatproof bowl over the pot and ensure that it is not touching the surface of the water. 

Add the egg whites, granulated sugar, and cream of tartar to the bowl. Whisk constantly for 4 to 5 minutes, or until the mixture is white, foamy, and reaches 165 degrees F on an instant read thermometer. 

Transfer the egg white mixture to the bowl of a stand mixer fitted with the whisk attachment. Beat on medium speed for 3 to 4 minutes or until stiff peaks form. Add the vanilla and mix just to combine.

Spread the meringue over the pie and toast with a kitchen torch, if desired. This meringue is delicious both plain and toasted!