Preheat the oven to 350 degrees.
Grease and line a 10x15-inch jelly roll pan with parchment paper. Set aside.
Using a handheld mixer or stand mixer fitted with the whisk attachment, egg yolks and sugar until fluffy.
Add in vanilla extract and yogurt, mix until combined.
In a separate bowl, whisk together dry ingredients (flour, baking powder, salt, cocoa).
Add dry ingredients to wet ingredients, mix until combined.
In a separate bowl, beat the egg whites until stiff peaks form. Gently fold them into the batter.
Pour the batter into the prepared jelly roll pan and spread evenly throughout the pan.
Bake for 10-12 minutes or until the cake springs back when lightly touched.
While the cake is baking, place a tea towel on the counter and generously coat it with powdered sugar.
Once the cake is removed from the oven, immediately flip the cake on to the prepared tea towel and carefully peel off the parchment paper.
Roll the cake up with the tea towel and set it aside, allowing it to cool completely to room temperature.