Set out two medium-sized mixing bowls.
In one bowl stir together the flour, baking powder, cornstarch, and ¼ cup sugar.
In the other bowl add the egg whites. Put the yolks into the bowl with the flour.
Add the milk, beer, and vanilla extract into the flour/yolk bowl. Stir until just combined.
Add the salt and cream of tartar to the egg whites and beat on high with a hand mixer until stiff peaks form. Add the remaining tablespoon sugar and beat until well combined (adding sugar to the egg whites makes them more stable and able to hold up to being folded into the batter).
Fold the egg whites into the flour mixture.
Spray the inside of a round ring mold* with cooking spray, add to a skillet over medium/low heat or a griddle set at 275°F.
Pour the batter into the mold until it’s 2/3 full. Cook until the batter on top looks mostly dry. Flip while still in the mold until the bottom is golden brown. Remove from heat, remove mold.
Re-spray the mold with cooking spray and repeat until all batter is used.