In a large bowl whisk together 2 egg yolks, 1 tablespoon of the sugar, 1/2 cup whole milk, 1 teaspoon lemon zest, and 1/2 teaspoon vanilla extract until combined.

Sift the pancake mix over the wet ingredients and whisk to combine.

Clean and dry a medium metal or glass bowl and using the whip attachment on a handheld mixer, whip the 4 egg whites until they are very foamy, about 30 seconds. Add in the cream of tartar and whip on medium high until soft peaks start to form. Slowly sprinkle in the remaining 2 tablespoons of sugar as you continue to whip the egg whites. Once all of the sugar has been added, turn the mixer to high and beat until stiff peaks form and the mixture becomes glossy about 3-5 minutes total. *See notes.

While the pan preheats, add one-third of the egg whites to the batter.

Using a whisk, gently whisk to combine. Once that is well incorporated, use a spatula to gently fold in the remaining egg whites, being very careful to trap all of the air from the egg whites. Make sure to scrape all the way up from the bottom of the bowl for even mixing.

Very lightly spray the pan or griddle with a thin coating of nonstick spray, and the inside of the ring molds if using. Fill the ring molds spray, and the inside of the ring molds if using. Fill the ring molds 3/4 of the way with batter, about 1/4 cup. (See note below if you don't have ring molds.) Cover pan or griddle with a lid. Cook for 5-6 minutes. Check the pancake to see if you can flip it, the edges should appear dry. It is very delicate, but should come off the pan easily.

Remove the pancake from the ring mold and flip the pancake when it is slightly set and the bottom is golden brown. Cook the other side covered for another 3-4 minutes, or until the whole pancake is cooked through.