Preheat the oven to 350 degrees F.
In the bowl of a stand mixer, add the eggs, cream of tartar, salt, and vanilla.
Begin to whisk on medium speed. When the mixture starts getting frothy, slowly pour in 1 cup of the sugar.
Turn the mixer up to high and beat until stiff peaks form.
In a separate bowl, whisk together the flour and remaining sugar.
Fold the flour and sugar into the fluffy egg whites using a spatula very carefully. Be careful not to deflate the egg whites.
Carefully pour the batter into the ungreased pan. If you grease the pan the batter will not rise properly. Use a spoon to smooth the top of the batter out.
Bake for 30-45 minutes, until the top turns golden brown.
Turn upside down over a cooling rack and allow to cool completely, 1-2 hours.
If the cake has not slid out, use a butter knife to go around the edges of the pan to release it.
Best served with whipped cream and strawberries!