Place the egg whites in the bowl of a stand mixer fitted with a whisk attachment, or in a large bowl with a hand mixer. Beat on medium speed until the whites are starting to look frothy.
Add the cream of tartar (or lemon juice) and continue beating on medium speed until the whites are holding soft peaks. A tablespoon at a time, add the remaining ¾ cup of sugar to the egg whites while beating at medium speed.
Increase the speed to medium/high and whip to stiff peaks. They should look glossy and stand tall. Lightly sprinkle the dry ingredients over the egg whites. Using a silicone spatula, begin folding the dry ingredients into the egg whites.
Carefully invert the pan, place it on a stable surface, and let it cool upside down for 1 ½ hours. Once the cake is completely cooled, turn right-side-up, run a butter knife around the sides, the center, and the bottom of the pan, and remove the cake from the pan. Allow the cake to cool completely before serving.