Preheat oven to 350F. Cut a circle of parchment paper the size of the pot, spray the PAPER (not the pot) with cooking spray and put in sprayed side down. Do not spray or get grease on the sides of the pot.

In a medium bowl, whisk together the flour and half the sugar 91 cup). Sifted flour will help make it lighter.

In a stand mixer with a whisk attachment, add the eggs and whisk on medium until they start to thicken and foam Add the cream of tartar, and salt, and whisk for another minute on medium, then turn up the speed to high. Slowly add the other cup of sugar, and then the vanilla. Whisk on high until shiny stiff peaks form.

By hand, add 1/3 of the flour mix and fold with a rubber spatula until flour seems incorporated. Repeat with the remaining flour. Fold gently to keep the batter light an airy, without deflating the egg whites. Spread the batter into the prepared pot slowing and carefully. Keep the batter in the center a bit higher than the sides.

Bake for about an hour until the cake has risen and is lightly browned. It will spring back when touched. turn upside down onto a rack and let cool completely.

Run a knife around the side to loosen the cake, and turn out. Peel off the parchment paper. Serve with chocolate sauce,berries, whipped cream or your preference. Using a serrated knife cuts it best, with a sawing motion (not straight down).