I start by placing 5 egg whites, at room temperature, in the bowl of an electric mixer. Add 1/4 teaspoon salt and start beating with a whisk attachment. Once frothiness has been achieved, slowly start adding 1/2 cup granulated sugar and a large pinch of cream of tartar. Continue to beat at high speed until the egg whites just begin to hold stiff peaks. Do not overbeat or the whites will become dry and start to separate. Mound the billowy, cloud-like meringue onto the tart and bake in a preheated 375˚F oven. I will not give you a length of bake time. Stand guard at the oven door and keep an eye on the browning meringue. Pull when it looks as it does above.