Set out a stand mixer (or a bowl and a hand mixer), a small bowl and a large bowl.
Separate the eggs, putting the whites in the stand mixer and the yolks in the small bowl.
Add the cream of tartar to the egg whites and beat on high until stiff peaks form, about 5 minutes.
Add the beer, buttermilk, and vanilla to the egg yolks, beat until well combined.
In the large bowl stir together the flour, sugar, baking powder and baking soda.
Add the yolk mixture to the dry ingredients and stir until combined.
Gently fold the egg whites into the pancake batter.
Add the butter to a preheated griddle (preheated to 350) or large skillet over medium high heat, push around until melted.
About ¼ cup at a time, pour the pancake batter on the preheated surface. Allow to cook until bubbles form in the center, flip and allow to cook until golden brown on the underside.