I've made this pie for over 40 years now and it's still our fave!

The second step is to bring the ingredients to a boil while stirring constantly over medium heat. Bring to a boil, then take off the heat.

3. Whisk in half of the heated mixture into the beaten egg yolks, one third at a time. Return the mixture to the saucepan and stir continuously.

4. Once the mixture has thickened, return it to a low boil and simmer for another minute.

5. Take it off the heat and mix in the butter, lemon zest, and juice until everything is incorporated. Delay serving until the lemon filling reaches a warm temperature.

Set the oven temperature to 325°F, which is 163°C. 6.

7. Create soft peaks by beating the egg whites and cream of tartar in a large, clean mixing dish. Beat in the sugar, 1/2 cup at a time, until stiff peaks develop.

8. To make the lemon filling lighter, gently fold in the beaten egg whites. After the pie shell has baked, spoon the filling into it.

The center should be set and the top should be somewhat brown, which should take around 25 to 30 minutes in the oven. 9.

Turn off the oven and set the pie pan on a wire rack to cool.