Preheat your oven to 375°F (190°C).
In a large mixing bowl, combine the flour, sugar, and salt. Add the butter and use a pastry blender or your fingers to work it into the flour mixture until it resembles coarse crumbs.
Press the mixture into a 9-inch pie dish, making sure to evenly cover the bottom and sides.
Chill the crust in the fridge for 30 minutes.
In a separate mixing bowl, whisk together the eggs, lemon zest, and lemon juice.
Remove the crust from the fridge and pour in the lemon mixture.
Bake the pie for 35-40 minutes, or until the filling is set and the crust is golden brown.
While the pie is baking, prepare the meringue topping. In a clean mixing bowl, beat the egg whites and cream of tartar until soft peaks form. Gradually add the 1/2 cup of granulated sugar and continue beating until stiff peaks form.
Remove the pie from the oven and spread the meringue topping over the filling, making sure to seal the edges of the pie.
Return the pie to the oven and bake for an additional 15-20 minutes, or until the meringue is golden brown.
Allow the pie to cool completely before serving.