Preheat the oven to 350F and line two 8x8 square pans, then set them aside.
In a large bowl, add the eggs, egg yolks, and sugar. Using a hand mixer or stand mixer, beat the mixture on medium-high speed until it becomes thick and pale in color.
Add the shifted cake flour in three additions and carefully fold the batter to avoid losing too much air.
Next, add the melted butter and fold it into the batter until well combined.
Divide the batter equally between the two prepared pans.
Bake for 20 minutes, then let the cakes cool completely.