Separate the eggs, and beat the whites until stiff peaks form. Set aside.
4 eggs, separated
Cream the butter and sugar. Add the egg yolks, flour, and salt. Mix.
2 Tbs. butter, softened, 1 1/2 c. white sugar, 3 Tbs. all-purpose flour, pinch of salt
Add the lemon juice, zest, and milk. Mix well.
2 med. lemons, juiced (about 1/2 c. juice), 1/2 - 1 tsp. lemon zest, optional, 1 1/4 c. whole milk or 2% milk
Gently fold the well-beaten egg whites into the lemon mixture. You want to keep the airy foamy consistency.
Pour the mixture into an unbaked 9" pie crust.
1 (9") unbaked pie crust
Bake in the bottom half of the oven at 350° for 25 minutes. Reduce the temperature to 325° and continue baking for another 30 - 35 minutes. (It may still jiggle a bit, but not too much.)
Cool and refrigerate for several hours (or overnight) before serving.
Notes
You can use bottled Real Lemon, but it doesn't produce the same fresh flavor as using freshly squeezed lemon juice.If desired, serve the lemon pie topped with sweetened whipped cream.