3 egg whites
1/8 tsp. cream of tartar
1/3 cup super fine sugar
Preheat oven to 425 F.
Put egg whites in a bowl and place that bowl over another bowl of hot tap water to warm them up.
Using your mixer on low speed whip the whites until they start to be frothy.
Add the cream of tartar. Bring up the speed and whip until soft peaks.
Add the 1/3 cup sugar a little bit at a time and and whip to stiff peaks.
At stiff peaks, rub a bit of the whipped whites between your fingers to make sure they are not grainy. You want to make sure all the sugar is dissolved or this could lead to weeping in your meringue — where the topping starts to get watery. Keep whipping until smooth.
Spread the filling all over the pie starting in the middle--making sure you touch all the edges of the crust to anchor the topping and to prevent shrinking in the oven. You can swirl some peaks into the topping with a spoon.
Put the pie into the oven for about 5 minutes or til the meringue has browned.
Remove and let cool completely before serving or putting in the fridge. Once refrigerated the pie may begin to weep more quickly so try and put the topping on as a final step and leave the pie on the counter before serving.